225 carb 1997 no timing advance

Bought a used 3.0 225 carb, sn 541559, would not rev up and plane, just dies when you advance throttle, revs on muffs. Timing does not advance when revved in neutral on muffs

Powerhead is a Merc repower 2004 vintage, compression 115-120 everywhere
ECU is 83044-4
Not beeping any warnings.
Took powerhead off and exhaust plate and cleaned out tuner
put Champion Ql77plugs in
Tested TPI set to .95, moves smoothly to 3.8v Timing around 0
Tested crank pos sensor
Tested Stator 11 ohms
Cleaned out carbs

Substituted TPI, CPS and stator from efi parts motor, also temp sender, all parts test within spec
Sparks will jump 3/8 gap on tester

Put in set of Carson Sport reeds
Rebuilt fuel pump
Changed fuel lines and bulb
Repaired bleed lines and checked check valves
Engine idles well now.
Voltage 14v

Still have timing problem, seems to stay timed 4-10 atdc when revved on muffs
Talked to Chris Carson, and Simon, both feel ECUs pretty reliable.

Anyone else have any thoughts, I'd love to get a ride this season!! It is on my 21 Sanger and I'm hoping to run a 25" prop to about 70mph.

I pulled all conduits off and looked wires over and seem intact, I am about at the end of my patience here, seems like I've followed all the directions.:crying:

Thanks, Dave Leonard

Dave:

Welcome to BBC! :thumb up2:

A couple of things I'd recommend:

(1). Provide COMPLETE serial number (including the digit and letter at the beginning).

(2). Verify CPS air gap. Recommend gapping at .050" for best results.

(3). Double check TPS readings, and watch for any glitches in it's operation (whatsoever).

(4). Fabricate and install TWO (2) 10 ga. grounds at the back of the engine. One installed where the CDM's ground to the electrical plate, the other installed to one of the mounting bolts for the Ignition ECM. Each should be grounded to the same bolt the NEGATIVE BATTERY CABLE attaches to.

(5). If, after the above, the problem persists, I'd recommend replacing the ECM with a known-good, APPROPRIATE PART NUMBER ECM.

Thanks Don, the ECM is actually the right part # I think. It is actually 830044 7 which seems like the right one by application. I will fab those grounds and adjust CPS, TPS seems very consistent and smooth in its rising voltage.

I really appreciate your help.

thanks, Dave Leonard

SN is OG 541559.

Serial# 0G541559
Model# 1225413TD
MERCURY 3.0L 225EFI L

Obviously, if it's carbed (currently), it's some form of a "FrankenMerc" (been modified).

Any chance you can post a picture of your ignition coils?

Attachment 21625Attachment 21626Attachment 21627Attachment 21627Don, some Pics, also last number of sn I gave you seems to be a zero not a 9

Correct data:

On the powerhead, which is an august 2004 merc repower;
sn Qscc024780s1Pn 809794r97
Mod225/250
On the trim bracket:


Sn og541550
Mod225 xl
1997

Quote:

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Originally Posted by Zoomba

Attachment 21625Attachment 21626Attachment 21627Attachment 21627Don, some Pics, also last number of sn I gave you seems to be a zero not a 9

Correct data:

On the powerhead, which is an august 2004 merc repower;
sn Qscc024780s1Pn 809794r97
Mod225/250
On the trim bracket:


Sn og541550
Mod225 xl
1997

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That's more like it.... and clears up the "FrankenMerc" possibility:

Serial# 0G541550
Model# 1225422TD
MERCURY 3.0L 225 XL

Your ignition ECM, coils, etc. appear to match that serial number.

Go back to my first reply (above) for recommendations. :thumb up2:

Don, I think we may have success,

I made 10 gage ground wires and installed as you recommended, also used Caig DeOxit http://store.caig.com/s.nl/sc.2/category.188/.f contact cleaner aggresively on the ECU multi pin plug. Hosed plug and worked the connector inn and out. This stuff is great, also coated grounds with it.

About 10:30 tonite went out and fired her up on the hose. Good thing I live in the woods, a 3.0 2stroke has quite the demented howl late at nite running on a hose, sounds like a pissed off wolverine on crank! My neighbors must have thought the Texas Chainsaw Massacre was going on next door.


Timing seemed to be going up to over 10 btc revving on the hose, and going way ATC when the throttle closed, so at least 20 -30 degrees of timing motion, which really was not changing before. Will run down to lake or possibly the Bay for a test blast in the AM.

Is there any data for advance relative to RPM? I am assuming the timing is now following the TPI and retarding ( like the owner) as the throttle closes.

Thanks for the help, hopefully the boat will now get up on plane and not just die when the throttle gets opened.

Dave Leonard

Timing is ECU controlled (based on inputs from various sensors).

If you did not have good connections (including the ground connections), it may have had your timing FIXED.

See how it does... be sure to report back. :thumb up2:

Timing fixed, but it still won't go in the lake.

It really seems like it is idling okay, then begins to sneeze and when you advance throttle it just dies, seems like running out of gas.

I have had the carbs apart 2 times never rebuilt, seemed like the needles and seats were opening, closing etc. I ran the boat in the lake and hooked up my spare TPC and tuned it for .95 and then advanced it with engine running by hand and the timing moves thru full range, 22 before, 2 after etc.

I have a whole spare 1997 seized 225 EFI that came with the deal, I cleaned out the vst tank and then put a shop tank on, filled with gas and powered, seems to build fuel pressure.

Would it make sense to convert this carb motor with this EFI setup, I have the entire harnesses and the matching ecus. Can I run it with the carb ecu or do I need the efi ecu, and if so will the CDMs work with the EFI setup? Is this a waste of time or a great solution?

Seems like it should run with carbs but I'm beginning to wonder if I have a fuel problem. I checked the pulse pump and it seems to put out a lot of fuel, and the bulb squeeze is firm and does not affect the running, it stilll seems to be sneezing a lot. In never sneezes at idle on the muffs, but seems to not like being in the water. The sneeze gets worse at idle the longer it runs, seems like it almost is running out of gas.

The Carbs seem to have the correct jets, I suppose I could have sticky needles making the engine lean. Wish I could duplicate the problem in the yard, pain having to launch to test and having the same problem.

I have an inboard ski boat in the lake, and a 21' 5.7 merc wellcraft in the bay, why am I spending my free time wrenching instead of running my great running boats? Just wondering . Think its a need for speed thing.

Thanks, Dave

Sounds like it needs the old fashioned sync'n link. Timing of the carb advance and spark advance synchronized together.

carb rebuild may be in order. Seems like that was always one of the first things mechanics turned to in the day.

dont know if the intakes would fit from the EFi motor but EFi was a huge improvement over the carbs. Don will have to fill in on the feasibility. You would definitely need to swap out the ecu as it runs the injectors. Probably the whole wiring harness.

I definitely agree that a complete Sync-n-Link proceedure is in order (and that it may be wise to completely tear down the carbs, cleaning every single jet and passage while apart).

As for the EFI question- it CAN be done. You would essentially need to strip the engine down to the BARE POWERHEAD (no fuel, electrical, or bleed system)... then set and transfer ALL components.

However... this does bring into question a couple of items on the EFI's history:

1. WHAT was the original cause of it "seizing"? If not corrected- you're very likely to repeat history on ANOTHER powerhead.

2. How long has this engine been SITTING? At the very least, I would recommend that the VST be completely cleaned, and the injectors be cleaned/flowed/serviced prior to placing them back on another powerhead. :wink:

Thanks Guys, I have done sync and link a couple of times, and I also think total carb rebuild is the next place to go, it seems like the engine should run with them, and the FI conversion is potentially very expensive, probably should have dug all the way thru the carbs first. I did pull them off and squirt carb cleaner thru all the jets and reassemble, but carbs always seem to work better with new needles, seats etc.

Thanks, Dave Leonard

Rebuilt carbs, changed wrong spec carbon core wires that were on there for new Copper core OEM wires from Don.
Enjoyed very fast service from Rhonda.

Put boat back in water.. salt this time ad ramp esier to get to and float is big enough to tie boat to and add power to test. Once again engine misfires and will not run more than 2000 rpsm or so. Seems to run a lot worse in water than on hose. I am beginning to think I have some bad CDM s, I have an oscilloscope so I am thinking I need to figure out haow to use it and check the dvm? Do these CDMs seem to fail, they throw a nice spark over 3/8 " on tester, but I have definitely had plug wires that fail under higher cylinder pressures.

Are these testable, should I consider throwing 6 CDMs at the engine?

It seems to be the last thing that can be wrong, as I've done everything else!

Thanks, Dave Leonard

I noticed you said you installed QL77 plugs. Are they QL77CC plugs? That's what you should be using.

Quote:

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Originally Posted by Props4u2

I noticed you said you installed QL77 plugs. Are they QL77CC plugs? That's what you should be using.

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+1.... QL77CC (Champion) is the recommended plug for this engine.

Also... DID YOU PERFORM A COMPLETE SYNC-N-LINK PROCEEDURE AFTER RE-INSTALLING CARBS?

It IS Mandatory. :wink:

Hey thanks for sticking with me thru this problem, I think I found it!!

This diagnostic procedure was shared with me by Chris Carson, thanks Chris for this.

I Indexed the flywheel using white tape and numbers for each cylinder, this can be done quite quickly by measuring and measuring a piece of wire or zip tie over the 30 degrees marked on the flywheel timing marks, doubling this distance, and then using this piece of wire or cut off zip tie for a reference measurement stick 1/2" long pieces of tape on the flywheel every 60 degrees, which pretty well correlates with tdc on each cylinder. You then go around a second time and then mark tape precisely with vertical lines using the 60 degree measuring tape you just made, lay it around the flywheel, and mark to find TDC for each jug.( not super accurate but pretty close), and mark the cylinder numbers with a sharpie, around the flywheel counterclockwise on the pieces of whit tape. I measured in both directions to minimize additive error, and average it out.

Take plugs out so engine turns easily and will not start.

Put in plugs, start engine, check timing on each cylinder, at idle and at higher revs to make sure timing is advancing on each cylinder.

Each plug wire should then be checked with an inductive timing light, and the corresponding number marking on the flywheel should come up under the timing pointer on the flywheel.

Started engine and moved timing light pickup to each cylinder , all good until cylinder #4, on cylinder 4, the timing was bouncing around and was corresponding with cylinder 3's marking, but not very well. Sometimes it was halfway between 3 and 4, and bouncing 30-40 degrees. When I advanced the throttle it would move to 4 where it was supposed to be, steady out, and then at about 2k rpms just stop firing and go dark.

Surreal as it was dark by then tonite so it got real dark, came back on below 2k each time, then steady at 4 mark till idle then back to bouncing.

Put timing light on all other cylinders, and they were steady and advancing in proportion to revs as advertised.

I tried another CDM and could not get the problem to move off cylinder 4.

Finally occurred to me ( went in to watch political debate, fell asleep had a great nap and figured it out...)

HARNESS!!

Woke up , went out at midnight, and pulled pin connector from #4 CDM, BINGO burned/missing black ground wire socket connector on .cylinder 4 harness side connector.

Interestingly #4 CDM appears to be newer than all other CDMS, I think this problem may have plagued more wrenches than just me and the previous owner.

Sure glad I did not yield to last nights temptation to buy 6 cdms, and listened to the people who told me not to replace ECUS etc, all it took was 2 months of troubleshooting!



I am hopeful I'll finally get a ride this weekend, thanks for all the help

Dave Leonard

Good catch- Dave!

That's a tough one...

Replacement CDM connectors should be available, if necessary (or perhaps you have one on your other parts motor). :wink:

Thanks Don, I have the parts harness, so I will use one of those connectors, figured I'd use a few bell type crimp connectors and some liquid neoprene.

It is almost always simple, once you figure it out, glad I did not start throwing parts at it! ( well besides plug wires, carb rebuild kits, CCM reeds, fuel pump diaphragms, fuel lines, clean out tuner, new plugs.... 0 But in my little world, those are all great tune up parts and I should end up with a strong running motor just in time for the lakes to freeze and turn into snowmobile drag strips. How are you at fixing sleds over the internet?

Dave

Quote:

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Originally Posted by Zoomba

Thanks Don, I have the parts harness, so I will use one of those connectors, figured I'd use a few bell type crimp connectors and some liquid neoprene.

It is almost always simple, once you figure it out, glad I did not start throwing parts at it! ( well besides plug wires, carb rebuild kits, CCM reeds, fuel pump diaphragms, fuel lines, clean out tuner, new plugs.... 0 But in my little world, those are all great tune up parts and I should end up with a strong running motor just in time for the lakes to freeze and turn into snowmobile drag strips. How are you at fixing sleds over the internet?

Dave

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Good job sticking with the problem and solving it! Fellow snowmobile drag racer here.Hoping for ice too!