Johnson 90HP V4 not idling and dies, j90sleoc

[bluecrab]

Hello guys, I am new to the forum as a member and first of all I would to appreciate the vast amount of info it is shared here by all of you, I have been reading and posting on other forums but had no luck whatsoever, and I hope my post and resolution if any, helps someone else like me out there.. Here I come:

My engine: Johnson 90HP V4, J90SLEOC ocean runner 60 degrees
Compression 120,119,118 and 112.

It starts, goes up in RPM at about 1100 and then slowly comes back down until it dies, also it kind of coughs by the exhaust, it does not idle
I am using a small portable tank with new fuel premixed 50:1 with only a small inline filter and the bulb/hose plugged straight into the engine filter.
-checked sparks and they were very weak and found the coils in very bad shape and rusty, they were replaced alone with new plugs recommended for this engine.
I have spark now jumping the famous 7/16 open air gap….but engine keeps doing the same
--although the previous owner tried to fix it and showed me his bills from the mechanic rebuilding the carbs, I decided to go ahead and order new kits, the carbs were already cleaned when I opened them; however, I placed them in chemdip for 24 hours each, every high speed screw removed and cleaned apart, every orifice sprayed, cleaned, blew it with compressed air, new gaskets, seats, valves…heck even new floats with new bowls as the old ones were a bit curved…these carbs are like new
--the intake was cleaned in very detail too and got new gaskets (big o-rings) as the old ones were kind of flattened
--I found a leak on the primer solenoid and ordered a kit and fixed but the problem did not go away.
--then also noticed that the pump which was a VRO premixed style was leaking also on the bottom. Decided to order parts and found it was too expensive as one of the plastic cover is cracked so I ended up buying a premix standard one from that site they called max rules which they told me it was supposed to work with my engine..So new pump in, I give it a few cranks and can see burst of fuel out of the hoses going into carbs/intakes..
Guess what?....did not solve the problem either
I continued checking and noticed that low noise when priming with the bulb and found the vapor/fuel separator with some sort of leakage…dammm new parts again…but did not solve the problem…
I went ahead and bought the Original OMC service manual and follow every possible recommendation
--shift rod adjusted by the manual correct height…
--checked/adjusted link/sync.
--then per the manual I needed an expensive tool to set the timing and I ended up buying another tool from a very knowledgeable person which happens to be in this forum (I hope he jumps in and give me some advice), anyways I set the timing per his instruction using the easy timer and as the attached pic shows I set the idle to 4 degrees ATDC..

The engine does the same thing although it lasts longer before dying and keeps coughing……I notice that when going down in rpm and trying to die I can continue rev..ing it up by pushing key in and allowing the solenoid spraying fuel into intake…that makes me think of bad fuel flow into carbs…but the pump is new, it pumps as I confirmed seeing burst of fuel coming out of the lines, also this does not happen by pressing the bulb, when the engine start dying if I press the primer bulb and try to get it going, it gets hard quick but the engine dies anyways…do not idle at all…
No way the carbs are dirty or gummy…no…they are as clean as new, twice I have checked them, part by part..
I have all the idle screws set at 6 turn each, the manual says to start at 3 but in other forum they told me six turns is the appropriate.

I have no leaks at all…

The engine is on muffs on the trailer and that I am in the process of building a special big test tank….
Over the weekend I will go revisit again, sparks and linkage but I was wondering if anyone here is kind enough to share any expertise on what else could give me this problem. I am far away from being a mechanic but would like to learn and see if I can fix this old boat which my son I fell in love with.

I appreciate any help.

Thank you all.

[ChampioNman]

Welcome to the forum..I see you are from south Florida where abouts? I see you rebuilt the carbs with new kits and then later installed new bowl floats because they were curved? this leads me to believe you used after market carb kits true? OEM kits come with the floats along with other parts. If you used the white nylon washer under the needle seat you need to go back in and remove them as that effects the float drop. They aren't used in your motor. I also see you removed the "high speed screw"? The High speed orifice is in the carb bowl and is an orifice not an adjustable jet. You may be referring to the idle adjust jet. What did you set those to?
Is the vent open on your portable tank? There isn't a need for an additional fuel filter when connecting to the motor's filter for test purposes but that is OK. Try connecting directly from the fuel tank to the inlet of Max's fuel pump and make sure you have good vacuum from the pulse limiter to the pump as the vacuum from the crank case drives the internal diaphragms on the stacked pump. Connecting directly to the inlet will eliminate the vapor tank float.

[316jughead]

Welcome, ChampioNman is one of the guy's I told you about. One thing about getting help here is answer all questions, that's the only way we can get the info needed to help.

[bluecrab]

Welcome to the forum..I see you are from south Florida where abouts? I see you rebuilt the carbs with new kits and then later installed new bowl floats because they were curved? this leads me to believe you used after market carb kits true? OEM kits come with the floats along with other parts. If you used the white nylon washer under the needle seat you need to go back in and remove them as that effects the float drop. They aren't used in your motor. I also see you removed the "high speed screw"? The High speed orifice is in the carb bowl and is an orifice not an adjustable jet. You may be referring to the idle adjust jet. What did you set those to?
Is the vent open on your portable tank? There isn't a need for an additional fuel filter when connecting to the motor's filter for test purposes but that is OK. Try connecting directly from the fuel tank to the inlet of Max's fuel pump and make sure you have good vacuum from the pulse limiter to the pump as the vacuum from the crank case drives the internal diaphragms on the stacked pump. Connecting directly to the inlet will eliminate the vapor tank float.

Thank you Sr. very kind of you responding and welcoming me, very much appreciate it.
Please I apologize if I did not described it accordingly.
Yes I used the OMC carb kits and they come like you said. I did not used the plastic washer on the needle seat since they did not have it when I got them, everything else in the carbs are very detailed, cleaned twice, the high speed screws I mention were removed the from the old bowls, inspected them, placed them in chemdip, passed a fine steel wire through each one of them, blew them with compressed air and screwed them into the new bowls just tight enough until it stops same way I found them.
The little inexpensive filter I have in my portable I use it because this 3 gallons tank was recently purchased and we use it on our dingy with the other 15hp johnson. But I could remove it and see what happens.....the vent is open..I might open even more today when I get home....believe me I am taking notes from you guys....lol
the pressure from the limiter I suspected earlier that it was not enough because a friend of mine allowed me to use a standard pump and saw a weak fuel coming out......I did not have a baseline to compare to..so as an inexperienced newbie...I went ahead and bought a new pulse limiter...one of the blue ones and used a Stainless steel clamp to attach it to hose instead of the wire ties that had before...just in case...
If time allows me today I will do the test connecting the fuel line straight into the pump inlet and see what happens....again, thank you a lot for your input. I will keep posting results soon....thank you Sr!....

[bluecrab]

Thank you Sr!...your tool was of a great help!..and so your knowledge and kindness....I will follow today ChampioNman recommendations and post back with results....hey...perhaps someone read our emails via email....south florida is getting the first bit of cold weather this weekend.....hahah!!....although is just around 50....but that'd help bringing the kingfish and Spanish mackerel close to shore...
Thank you once more..I will keep updating...!!!!

[ChampioNman]

Sounds like you are on the Atlantic side. I'm up in Tally and it has been a miserable week here highs in the mid 40's and rain (much needed) all week. Low on Monday will be close to 30*. Wife's sister and BIL live in FLL.

[316jughead]

Poor baby, it was 17 here this morning, going to warm up this weekend. omcforever has on two pairs of long johns. If this computer doesn't stop making typing mistakes, I'll have to get another one.

[omcforever]

Poor baby, it was 17 here this morning, going to warm up this weekend. omcforever has on two pairs of long johns. If this computer doesn't stop making typing mistakes, I'll have to get another one.

18 now and dropping,,,,,,yep on the johns.

[omcforever]

On the roof at work(10th floor) servicing air handlers..

[316jughead]

On the roof at work(10th floor) servicing air handlers..

That sounds like fun. As a young man I worked construction, funny how I could freeze at work, but the cold didn't bother me Goose hunting.

[Bassmeister]

On the roof at work(10th floor) servicing air handlers..

Another reason I got out of steel erection.....seems I was always stuck in Ohio during the winter and Texas in the summer....

[ChampioNman]

Poor baby, it was 17 here this morning, going to warm up this weekend. omcforever has on two pairs of long johns. If this computer doesn't stop making typing mistakes, I'll have to get another one.

Nice thing about Florida, It will be in the 70's by midweek.

[bluecrab]

Today that I have all day free to play with the engine as the wife and kids are leaving for a birthday party...it's been raining since very early in the morning...no luck at all; hopefully later on the rains tops and I will be able to check and post results back...
The weather around this time of the year is really nice down here to be outdoors.....even better for the fresh water fishing, last week my neighbor got a 4 pounder peacock bass in our backyard. I have a couple of buddies up north around Chesapeake bay and they are always complaining about the cold...I always tell them....come to Miami around June-Sept and you'll see what really hell of the weather is all about....90 degrees and humid......anyway guys I was just hoping to post back in the results, maybe later when the rain stops....hey at least at 17 degrees a cold one just gets colder!!....lol
regards from South Florida.

[bluecrab]

Howdy ChampioNman, Today in between rain and clouds...I was able to revisit the linkage again, adjusted a bit with more accuracy, tested and same thing, then I went to follow your advise and connected the fuel line directly to the pump inlet and the results are the same, the engine starts right up, it goes up in RPM and then when it goes down about 800 RPM or so it dies, I can only extend its running a bit more although very rough by pushing the key in as I said earlier, I also played with the idle screws a bit by opening a bit more little by little and testing and it just gets worse when I get to 7 turns...then I decided to go back from beginning as per the OMC manual and ended up in between 6-7 turns but same results...ooh almost forgot as soon as the engine dies I went to check the carbs and unscrew the drain and all were full of fuel.....so I guess the pump is working fine....what do you guys think?....
earlier today my neighbor across the canal got a few big peacock bass using live bait....man they were big....as soon as a little cold front moves in the fish starts to move inland like
crazy.....I am not into placing videos or that kind of stuff but since this troubleshooting is driving me nuts, I just placed a small video on youtube of my engine symptoms, is not the best since it was by myself and I am a very shy guy, also that video shows the engine after it started first, dies and then I try to start it again, once it starts again the last part when I get it to run a bit longer is because I am pushing the key in....
any advise from the OMC guys here?....
the video is on youtube


appreciate it and hope you guys are having a nice weekend.

Regards,
The video

[316jughead]

That is one sick sounding puppy. Spark plugs Champion QL78YC gaped at .030? Are you raising the warm up lever on start ups? All carbs closed at idle and both sides of carbs opening at the same time? When you set the idle timing, are you sure that the timing base is against the stop, it has the spring on it to return it to the stop, and is moving free? I would move the big black timing roller away from the timing arm, verify that the timing base is against the stop, and recheck the idle timing, I still don't like where your idle tab ended up on the indents. These motors have to idle rich, and idle better with ATDC timing, you can sometimes compensate on the motors with adjustable idle orifices, by turning them way out. Your motor does sound like some I've heard with NGK spark plugs. We can go into throttle cable adjustment and sync and link after we digest this or get some more info from Fred, AKA ChampioNman.

[bluecrab]

Thank you 316jughead!..I always wondered why it was not possible to give throttle without engaging gear via the remote handle. My friend also asked me as his handle has that lever you mentioned although his engine is a different brand. The sparks plugs I am using were purchased according to the OMC manual...I hate to think they are wrong since I purchased a set of eight to have spares on board....but if you think I should change them I could give it a try, check the attached sparks pic, I am using the QL77JC4 calibrated at .30. regarding the timing, I followed your recommendations very carefully, I have to admit that the tabs now are not on the place they were before I started messing around with timing; however, it gives me the 4 degrees ATDC and around 20-21 BTDC a full throttle. something I am very concerned about is that when I initially started giving some basic maintenance and checking the engine before everything else, I noticed lower unit needed to be checked for the basics as this boat was abandoned, the shifting was terrible hard and it needed to be looked at so I removed the lower unit and along with new water pump I also gave it a new shift rod o-rings and enclosure as well as a correct height adjustment. I mention all of this because I had to remove the shift linkage cable from its lever in order to work the lower unit, then when lower unit was finished, per the manual I tried to do some maintenance to the control cables, greasing them with correct OMC lubricants etc....that was when I think I messed them up because now I do not have to enough cable thread to play with the trunnions; however, it allows me to do the link and sync per the manual....now back to my remote handle, I wonder if those black wire ties it has is because they "invented" something to make it work instead of using the correct part....Today I am on standby at work and will probably need to work in the afternoon, if not I will curiously check that handle again, it's got to have some way to give throttle without engaging right?....man I though I got a good deal on this boat...do you thing I should get a new handle with control cables?...any brand recommendation?

as usual thank you so much for your input....and also thank you for sending us a really nice weather down south!!

Regards

[bluecrab]

Thank you 316jughead!..I always wondered why it was not possible to give throttle without engaging gear via the remote handle. My friend also asked me as his handle has that lever you mentioned although his engine is a different brand. The sparks plugs I am using were purchased according to the OMC manual...I hate to think they are wrong since I purchased a set of eight to have spares on board....but if you think I should change them I could give it a try, check&nbsp;the attached sparks pic, I am using the QL77JC4 calibrated at .30. regarding the timing, I followed your recommendations very carefully, I have to admit that the tabs now are not on the place they were before I started messing around with timing; however, it gives me the 4 degrees ATDC and around 20-21 BTDC a full throttle. something I am very concerned about is that when I initially started giving some basic maintenance and checking the engine before everything else, I noticed lower unit needed to be checked for the basics as this boat was abandoned, the shifting was terrible hard and it needed to be looked at so I removed the lower unit and along with new water pump I also gave it a new shift rod o-rings and enclosure as well as a correct height adjustment. I mention all of this because I had to remove the shift linkage cable from its lever in order to work the lower unit, then when lower unit was finished, per the manual I tried to do some maintenance to the control cables, greasing them with correct OMC lubricants etc....that was when I think I messed them up because now I do not have to enough cable thread to play with the trunnions; however, it allows me to do the link and sync per the manual....now back to my remote handle, I wonder if those black wire ties it has is because they "invented" something to make it work instead of using the correct part....Today I am on standby at work and will probably need to work in the afternoon, if not I will curiously check that handle again, it's got to have some way to give throttle without engaging right?....man I though I got a good deal on this boat...do you thing I should get a new handle with control cables?...any brand recommendation?<br><br>as usual thank you so much for your input....and also thank you for sending us&nbsp; a really nice weather down south!!<br><br>Regards<br>

[bluecrab]

[bluecrab]

[bluecrab]