115 Optimax Issues

[TritonTRXV8]

This unanswered question becomes much more critical, i.e. actual elapsed time. Either that, or the thermostat was stuck open.
Still some cold water out there.

+1. So critical to make sure the engine reaches at least 120 degrees at idle before takeoff. He did say he had a smartcraft monitor but did not remember the exact temps. I know I always have my mercmonitor set to the "water" page and watch the temp and psi all the time. Especially in the winter. Shame to see this happen tho.

[bishoptf]

I'm going to disagree with the lean-running assessment. DEFINITELY recommend the rail and all (6) injectors be cleaned, tested and serviced- but there is clear evidence (in the form of carbon deposits) atop that piston that indicate adequate fuel WAS being delivered.

If you carefully inspect the piston rings at the exhaust port area, you'll note GROOVES in the rings (the rings HUNG in the exhaust port). This in turn ripped a portion of the piston crown away, directly above the port.

The added friction caused by the damaged rings (and debris floating around/transferring from one surface to another) resulted in increased temperature in this area. Damage done to the "dish" area was likely either related to this increased heat, OR to debris that was compressed between piston crown and cylinder end (inspection inside block/cylinder would help with that determination).

I strongly suspect that sometime in the very recent runtime (within the last 3 hours) this engine did NOT reach operating temperature prior to acceleration. When this occurs- the cylinder wall liner does not properly expand, but the PISTON DOES (at about 40 times faster rate). Piston/rings essentially become larger than the bore- exhaust side of piston being the fastest expanding area. A piston ring extends to far into an exhaust port as the piston passes the port, and the ring catches the edge of the port (pictured above is the resulting damage).

Well I don't have three hours on it this season more like 30 min or so. I hear everyone about the warm up but I had to idle out of the no wake zone and its not a that short. The difference between pistons 1/2 and 3 is night and day. They don't even look close to being the same, 1 and 2 literally look brand new, the third looks like something has been going on for sometime.

I have attached more pics that show closer what the damage looks like and if you look closely at the center ring you will see one side melted. I still think that something was leaning out and that center ring is evident of that. My guess is bad/faulty air injector, according to my service manual Ican test it with a multimeter but not sure if this is a just a continuity test etc. I need to get new batteries for my MM but will do that later today.

I am replacing the impeller, wasn't planning on doing the thermostat or poppet will need to read some more and think about that one. I would like to have the rail serviced and all the injectors but it appears to be pretty pricey and there is a reason I am tearing this down myself . Something I need to think about and figure out which way to go, I'd like to have all of them serviced but its simply a monetary issue.

My samrtcraft monitor is junk in my opinion, its prolly the cheapest one since my only displays one thing at a time and you have to cycle through each thing one at a time, doesn't lend itself to be very nice when you are driving at the same time. I do get it now I will for sure watch my temps and make sure they are good before throwing the hammer, but if I am watching my temps I cannot watch my psi etc

I did call Sherms yesterday and talked to Max, very helpful, probably the third time I talked to him this week. He gave me the number of a shop in fort wayne IN, and I called them and talked to them. They appear to be able to take care of the block but I need to figure out how to ship the block to them, more fun :)

BTW when I disconnected the fuel line at the bulb, the fuel lines are toast, they have all of that gunk that Don has pictures of, really bad. I did pull the FF and check the filter I did not see anything in the VSP although I need to tear that down and look more closely. To that end I ordered new fule line from sherms and have that to do also.

Thanks again for all of the suggestions/help.

[bishoptf]

One more picture that tries to show the sleeve and scoring:
IMG-20140517-00057.jpg

[lfb6]

.......
If you carefully inspect the piston rings at the exhaust port area, you'll note GROOVES in the rings (the rings HUNG in the exhaust port). This in turn ripped a portion of the piston crown away, directly above the port.

The added friction caused by the damaged rings (and debris floating around/transferring from one surface to another) resulted in increased temperature in this area. Damage done to the "dish" area was likely either related to this increased heat, OR to debris that was compressed between piston crown and cylinder end (inspection inside block/cylinder would help with that determination).

I strongly suspect that sometime in the very recent runtime (within the last 3 hours) this engine did NOT reach operating temperature prior to acceleration. When this occurs- the cylinder wall liner does not properly expand, but the PISTON DOES (at about 40 times faster rate). Piston/rings essentially become larger than the bore- exhaust side of piston being the fastest expanding area. A piston ring extends to far into an exhaust port as the piston passes the port, and the ring catches the edge of the port (pictured above is the resulting damage).

There are things I don't understand (I know, that doesn't mean much but I'd like to ask at least):

-The piston rings are probably not made from aluminum but steel/ cast- something that expands more the way the sleeve would than the piston would, they have a gap allowing them some expansion (about 0.003 to 0.006 inches in diameter)
-If a piston ring could crack mechanically away a part of the piston wouldn't the ring crack itself?
-Everything looks more melted and not ripped away to me, both the area below the piston rings and above them and also the small material deficit on the crown?
-There is no debris around,would've expected at least a little bit on the piston head?
-bishoptf writes "had this happen a couple of times last summer but only at wot". That does sound more like slowly developing and like "warm seizure"?
Thanks in advance if someone would care to explain

But anyway: Would that change the way to rebuild this engine? Special precautions?

@bishoptf: Thanks for the latest pictures

How many hours ago did the engine start to stall if you remember?
Did you get the "not getting temperature" alarm when idling? (One beep in some minutes interval)

And yes, you're right: Servicing all injectors and rails seems expensive but I think it's essential now, especially as you're still thinking about a lean condition and after your check of the fule lines (even if the fuel filter should keep almost everything of that out of the system).
Concerning the direct air injectors there is a special procedure testing the valve movement (?), requiring a special tool and a dial indicator- don't know if it's a really good idea to do it yourself...

[bishoptf]

How many hours ago did the engine start to stall if you remember?

Did you get the "not getting temperature" alarm when idling? (One beep in some minutes interval)

And yes, you're right: Servicing all injectors and rails seems expensive but I think it's essential now, especially as you're still thinking about a lean condition and after your check of the fule lines (even if the fuel filter should keep almost everything of that out of the system).
Concerning the direct air injectors there is a special procedure testing the valve movement (?), requiring a special tool and a dial indicator- don't know if it's a really good idea to do it yourself...

Replies:


How many hours ago did the engine start to stall if you remember? Last summer maybe July/August, not everytime was sporadic, I was thinking the boost pump was going out.



Did you get the "not getting temperature" alarm when idling? (One beep in some minutes interval) No alarms when I was idling or running, no alarms at all until I ran the boat back to the ramp from my lift, looking back I probably should have had someone tow me back. I got an alarm right when I was at the ramp.


Someone tell me this, I pulled the lower unit off last night to replace the impeller and gaskets, then I read about having to have it in foward gear when doing the replacement. Do I have any issues with servicing the water pump side of things while the engine is on the stand?

[lfb6]

........ looking back I probably should have had someone tow me back. I got an alarm right when I was at the ramp.

Someone tell me this, I pulled the lower unit off last night to replace the impeller and gaskets, then I read about having to have it in foward gear when doing the replacement. Do I have any issues with servicing the water pump side of things while the engine is on the stand?

Thanks for the answers. I think after the first seizure the largest part is 'done' anyway- looking back I shouldn't have run my engine after the first time stalling either but afterwards you're always smarter...

The gear doesn't matter too much, it's just easier to get the driveshaft in another position in relation to the crankcase when the lu won't come up into position the last inch. Question is rather if you should mount lu or powerhead first?

[bishoptf]

Can someone answer me this, if the first two cylinders are good, do I need to have them re-honed and new rings put on those pistons? The only reason I ask is that a local machine shop I was talking to said that he woudlnt do it unless he honed the the first 2 cylinders and put new rings on them.

Anyone know who I can talk to and figure out whats the best process for the block?

[Nova Kaw 650]

I would prefer to re-ring the other two cylinders, if just for my own piece of mind. It's like having three new cylinders.

[TritonTRXV8]

Well I don't have three hours on it this season more like 30 min or so. I hear everyone about the warm up but I had to idle out of the no wake zone and its not a that short. The difference between pistons 1/2 and 3 is night and day. They don't even look close to being the same, 1 and 2 literally look brand new, the third looks like something has been going on for sometime.


Thanks again for all of the suggestions/help.

Keep in mind tho that as far as temps go if the thermostat is not functioning properly you could idle for an hour and it would never get up to operating temp. Thermostatic control only occurs at idle and as rpms and water pressure increase the poppet valve opens to allow straight water into the cooling system. Sounds like you have a Smartcraft system monitor and those are better than no smartcraft but only viewing one readout at a time is limiting. Maybe after all this is said and done a Mercmonitor would be a good investment.

[lfb6]

Can someone answer me this, if the first two cylinders are good, do I need to have them re-honed and new rings put on those pistons? The only reason I ask is that a local machine shop I was talking to said that he woudlnt do it unless he honed the the first 2 cylinders and put new rings on them. .........

The reason could be that one wants to avoid differences in compression between cylinders and get all the cylinders back to the same 'wear level'. Well, it's an almost new engine with 146 hours on it, piston, sleeves and rings on the other 2 cylinders are probably 'as new' concerning wear/ being within tolerances. You could take off the rings and measure the gap but...

What have you been offered concerning the bad cylinder? Is a new sleeve necessary or can it be bored and honed?

...... My samrtcraft monitor is junk in my opinion, its prolly the cheapest one since my only displays one thing at a time and you have to cycle through each thing one at a time, doesn't lend itself to be very nice when you are driving at the same time. I do get it now I will for sure watch my temps and make sure they are good before throwing the hammer, but if I am watching my temps I cannot watch my psi etc .......

Even with a MercMonitor it's not as easy- it delivers so much useful information that you wouldn't have it on the water page all the time. But if I'm not completely mistaken the SystemMonitor offers like the MercMonitor the possibility to connect easily instruments daisy chained via SystemLink. Don't know the list prices but sometimes you see them offered for ~40$ each? (Actually I'm considering doing this as I'm not too happy switching screens all the time to get back to the water screen....)

[SilverFox579]

Keep in mind tho that as far as temps go if the thermostat is not functioning properly you could idle for an hour and it would never get up to operating temp. Thermostatic control only occurs at idle and as rpms and water pressure increase the poppet valve opens to allow straight water into the cooling system. Sounds like you have a Smartcraft system monitor and those are better than no smartcraft but only viewing one readout at a time is limiting. Maybe after all this is said and done a Mercmonitor would be a good investment.

+1 and good points Roy. Even a system monitor will show temp, and that's where it should be set to confirm engine is reaching proper temp when boating in cold water. When I had one, I would scroll through to read temp, and once it was normal, then move to water pressure. I still do it that way today with my MercMonitor, only once I've confirmed proper temp, I move to Favorites which I've programmed to show important screens I want to see in 5-second intervals.

[EuropeanAM]

There are things I don't understand (I know, that doesn't mean much but I'd like to ask at least):

-The piston rings are probably not made from aluminum but steel/ cast- something that expands more the way the sleeve would than the piston would, they have a gap allowing them some expansion (about 0.003 to 0.006 inches in diameter)
-If a piston ring could crack mechanically away a part of the piston wouldn't the ring crack itself?
-Everything looks more melted and not ripped away to me, both the area below the piston rings and above them and also the small material deficit on the crown?
-There is no debris around,would've expected at least a little bit on the piston head?
-bishoptf writes "had this happen a couple of times last summer but only at wot". That does sound more like slowly developing and like "warm seizure"?
Thanks in advance if someone would care to explain

But anyway: Would that change the way to rebuild this engine? Special precautions?

@bishoptf: Thanks for the latest pictures

How many hours ago did the engine start to stall if you remember?
Did you get the "not getting temperature" alarm when idling? (One beep in some minutes interval)

And yes, you're right: Servicing all injectors and rails seems expensive but I think it's essential now, especially as you're still thinking about a lean condition and after your check of the fule lines (even if the fuel filter should keep almost everything of that out of the system).
Concerning the direct air injectors there is a special procedure testing the valve movement (?), requiring a special tool and a dial indicator- don't know if it's a really good idea to do it yourself...

The piston rings are steel, that is correct. They are, however, directly wrapped around the ALUMINUM piston (which is expanding rapidly).

The #3 cylinder sleeve is the FIRST to receive cold lake water on this engine model (as it enters the engine block)- so it's the most susceptible to this type of failure.

In the images that were recently added, you can even see where the rings are "bent" at the exhaust port area. These rings DEFINITELY hung in the exhaust port, ripping away (and fracturing) areas of the aluminum, which in turn burnt away rapidly as the poorly adhered (fractured) material disintegrated.

In regards, to gear position, it's only important that the shift shaft position match the gear position of the gearcase DURING ASSEMBLY. Personally, I prefer the NEUTRAL position for BOTH components (it's a much narrower "window" and less likely to result in error).

I would definitely recommend the damaged cylinder be resleeved, and ALL cylinders be honed, ALL wear components checked for proper dimensions, AND AT A BARE MINIMUM- the piston rings in the other cylinders be replaced.

[lfb6]

The piston rings are steel, that is correct. They are, however, directly wrapped around the ALUMINUM piston (which is expanding rapidly).

The #3 cylinder sleeve is the FIRST to receive cold lake water on this engine model (as it enters the engine block)- so it's the most susceptible to this type of failure.

In the images that were recently added, you can even see where the rings are "bent" at the exhaust port area. These rings DEFINITELY hung in the exhaust port, ripping away (and fracturing) areas of the aluminum, which in turn burnt away rapidly as the poorly adhered (fractured) material disintegrated.

Thanks a lot for the explanation! (I still don't get it how outboard engines survive. Pushing mine over 3000 rpm seeing the water temp drop instantly to 70 deg hurts every time...)

Is this a typical 2-stroke problem or actually an Optimax thing?

(Would still be interested in test results of the corresponding injector)

I would definitely recommend the damaged cylinder be resleeved, and ALL cylinders be honed, ALL wear components checked for proper dimensions, AND AT A BARE MINIMUM- the piston rings in the other cylinders be replaced.

Would you then replace the bearings, too?

[Nova Kaw 650]

The old Yamaha Banshee ATV's with the twin 2-stroke were notorious for cold seizing. Start it up and take off wide open for a minute; it's stops in a big hurry.
Once you get an outboard engine up to operating temperature for a few minutes, the sleeves have fully expanded. When the water pours in after the poppet valve opens, it can't cool the sleeves enough to shrink them appreciably.

[bishoptf]

The piston rings are steel, that is correct. They are, however, directly wrapped around the ALUMINUM piston (which is expanding rapidly).

The #3 cylinder sleeve is the FIRST to receive cold lake water on this engine model (as it enters the engine block)- so it's the most susceptible to this type of failure.

In the images that were recently added, you can even see where the rings are "bent" at the exhaust port area. These rings DEFINITELY hung in the exhaust port, ripping away (and fracturing) areas of the aluminum, which in turn burnt away rapidly as the poorly adhered (fractured) material disintegrated.

In regards, to gear position, it's only important that the shift shaft position match the gear position of the gearcase DURING ASSEMBLY. Personally, I prefer the NEUTRAL position for BOTH components (it's a much narrower "window" and less likely to result in error).

I would definitely recommend the damaged cylinder be resleeved, and ALL cylinders be honed, ALL wear components checked for proper dimensions, AND AT A BARE MINIMUM- the piston rings in the other cylinders be replaced.

I'd say its hard to tell if the rings are bent, they don't look bent at least to me but something happened and made things melt. So you would resleeve instead of boring the one cylinder and go with a merc larger size piston. The service manual lists 2 pistons one .0015 and one .0030 larger in size. I understand that the new sleeve would allow all three to be equal but still learning as to why when merc calls out larger pistons and I would assume they are matched somewhat to the other pistons, then wouldn't that be as good. Just trying to understand whats so bad about the larger piston, I mean I could re bore all three holes and go with the larger piston in ea one, but that is probably more expensive then just the one resleeve.

I haven't priced out the pistons but nothing on the motor is cheap ;)

Some picks of her torn down, all I have left is the compressor to remove and it will be ready to ship. Thinking of calling Chris Carson and see if he will mess with it or try to find someone local. I am close to Lake Of the Ozarks and I am sure they would have someone down there but would need to figure out who does good work.

Here is some more pics, couple without most of her clothes, and one of my boat all lonely and bored...

[EuropeanAM]

A PROPER rebuild of the engine would return ALL wear components to manufacturing tolerances.

That would include replacement of bearings, and EITHER returning all cylinders to (Standard) bore by sleeving- PLUS ensuring that any unsleeved bores are within tolerance, OR boring all cylinders to matching sizes (and replacing ALL pistons).

It is possible to bore only one cylinder... but I personally don't build engines that way. If you want proper longevity and performance, all cylinders should be at the same size (resulting in very close compression and overall displacement).

BTW... just out of curiosity, what part number is printed on the spark plug that was in that cylinder?

[bishoptf]

A PROPER rebuild of the engine would return ALL wear components to manufacturing tolerances.

That would include replacement of bearings, and EITHER returning all cylinders to (Standard) bore by sleeving- PLUS ensuring that any unsleeved bores are within tolerance, OR boring all cylinders to matching sizes (and replacing ALL pistons).

It is possible to bore only one cylinder... but I personally don't build engines that way. If you want proper longevity and performance, all cylinders should be at the same size (resulting in very close compression and overall displacement).

BTW... just out of curiosity, what part number is printed on the spark plug that was in that cylinder?

Yeah I can go that way, resleeving will cost more but its not terrible, not sure when they heat that up if it would effect the other two cylinders. At a minimum I was planning on replacing the rings and hone the first two cylinders, I haven't made up my mind about what to do with #3 yet.

The plug that was in it was an NGK IZxxx plug, whats marked on the side of my VSP you can't miss it, although my manual calls out a PZxxx plug. When I called the local marine service and asked them they told me to go with the IZ plugs and that is what I have been running, I have a new set ready to go in.

[EuropeanAM]

Should be IZFR5J (no other plug). Not to be confused with IZFR5G or IZFR6J, which are different plugs (and can cause problems if run in this engine).

[bishoptf]

Should be IZFR5J (no other plug). Not to be confused with IZFR5G or IZFR6J, which are different plugs (and can cause problems if run in this engine).

Yup thats the one, I ordered under NGK 5899 which is the IZFR5J, its on a sticker on the VSP you can't miss it. But like I said the service manual does call out a different plug, but those are the ones that I was running and will replace with, in fact I have at least 2 locations that call out different gap settings. The plug the manual calls out is PZFR5F, I assume the switched at some point.

[EuropeanAM]

Correct- they were switched to the Iridum plugs some time back.