still stumped. 1989 175GT

[tashasdaddy]

finally got to idle rough, will rev in neutral, but bog immediately in gear.

carbs spot, less, timing right on, link n sinced. spark atleast 1/2 inch with tester, no change when pulling spark plug wire.

i am at my wits end with this thing. vro still connected. could it be over oiling and fouling out?

 

[JasonAych]

Re: still stumped. 1989 175GT

Do these have reed valves? Going back to my 2 stroke Dirtbike days, what you are describing would point me to a bad reed valve or even a bad exhaust powervalve. I am pretty sure these do not have any kind of exhaust powervalves.

 

[JasonAych]

Re: still stumped. 1989 175GT

I am pretty sure I saw some sort of reed valves in my Service Manual for my 88 90hp.

 

[tashasdaddy]

Re: still stumped. 1989 175GT

yes they gave reed valves, but i am not getting any spitting back out of the carbs, that reeds usually cause.

 

[Lone Duck]

Re: still stumped. 1989 175GT

finally got to idle rough, will rev in neutral, but bog immediately in gear.

carbs spot, less, timing right on, link n sinced. spark atleast 1/2 inch with tester, no change when pulling spark plug wire.

i am at my wits end with this thing. vro still connected. could it be over oiling and fouling out?

Crank case gasket ? no change when pulling spark wire ?( doesn't stall ? ) I'm sure you've checked comp. Firing order ? What do your plugs look like to much oil ? Neutral switch ? disconnect helm wiring at the engine. Connect your own switches at the engine and fire it up.

 

[bktheking]

Re: still stumped. 1989 175GT

yes they gave reed valves, but i am not getting any spitting back out of the carbs, that reeds usually cause.

If it were over oiling it would be evident on the plugs? Typically a motor that revs in neutral but won't under load has an ignition issue. What the history as far as replaced ignition components?

 

[tashasdaddy]

Re: still stumped. 1989 175GT

ignition components i think is original.. plugs are good. new this week. after doing decarb. new gas with seafoam added. have disconected wiring harness and used test harness, with ignition switch.

compression is great, firing order OK.

neutral shift switch. i don't believe this age motor had one, can't find one on BRP diagram.

 

[bktheking]

Re: still stumped. 1989 175GT

ignition components i think is original.. plugs are good. new this week. after doing decarb. new gas with seafoam added. have disconected wiring harness and used test harness, with ignition switch.

compression is great, firing order OK.

neutral shift switch. i don't believe this age motor had one.

TD, try running it tonight in the dark and mist around the wires. Spark on all 6 plugs?

 

[JasonAych]

Re: still stumped. 1989 175GT

yes they gave reed valves, but i am not getting any spitting back out of the carbs, that reeds usually cause.

Although I'd agree that would be an obvious sign, I don't think it rules it out. If you described the symtoms the way you did and it was 88 Kawasaki KX125(dirtbike) you were talking about I'd bet money on it. But then again, it isn't a dirtbike engine. But then again, a 88 Kawasaki KX125 engine is pretty much a looper.

You've ruled out just about everything else.

I like the idea of looking for leaking spark in the dark.

 

[ezeke]

Re: still stumped. 1989 175GT

Did you pull the flywheel and check the magnets?

http://cdielectronics.com/downloads...09 - OMC Flywheel Trigger Magnet Location.pdf

 

[bktheking]

Re: still stumped. 1989 175GT

Did you pull the flywheel and check the magnets?

http://cdielectronics.com/downloads...09 - OMC Flywheel Trigger Magnet Location.pdf

Ezeke, I thought if the magnets move it throws timing out to the point where they won't run, they backfire and act up?

 

[capngregorus]

Re: still stumped. 1989 175GT

Had the same problem on my 88 crossflow after accidentally running it with 4 stroke oil.

We'd cleaned everything out to try to get it going again, finding lots of a clear, silicone like residue in the fuel lines and pumps. Carbs were spotless as id rebuilt them right before the incident.

I'm pulling it down now and keep finding the black residue of the oil in every vacuum line, and the nipples connecting to them.. Maybe that could be causing the problem.

Its getting a rebuild now since one of the cylinders was 59psi and 2 others 70 so it'l be a while before i can tell you if thats what the problem i had in mine was, maybe this might help you in the right direction..

Maybe someone made the same silly mistake i did.
Greg

 

[Lone Duck]

Re: still stumped. 1989 175GT

You said when you pull the plug wire there's no change. What do you mean ? It doesn't stall or what ?

 

[tashasdaddy]

Re: still stumped. 1989 175GT

there is not change in rpms. remember it is a 6 cyclinder. will pull flywheel today if rain holds off.

 

[emdsapmgr]

Re: still stumped. 1989 175GT

Any signs of water intrusion in the lower cylinders? It's not unusual for these V6 bubble backs to leak cooling water from the inner exhaust cover into the exhaust chest and into the (lower) cyls. It may knock one or two cyls out a idle, but may clear up at higher rpm's. Have you run it off a separate tank with new fuel (water in original fuel tank?) This may not specifically relate to your issue, but I offer it as a possible thing to check: These carbs had the plastic carb bowls on them-all of which will warp with age sooner or later. The bowl mating surface with the carb body will get out of flat. Usually this just causes fuel leaks, esp when the engine is tilted for shallow water running. In extreme cases, the warpage can disrupt the sealing surface by the high speed jets pipes and can cause them to run lean. OMC had a factory service (bowl) kit for the problem.

 

[kenmyfam]

Re: still stumped. 1989 175GT

How are the plugs ?? mine oiled like crazy when the fuel pump started to fail.
Are you on the muffs for this ??

 

[tashasdaddy]

Re: still stumped. 1989 175GT

plugs are clean, both muffs and at the ramp. does the same thing. as soon as i get my helper out of bed, will pull flywheel before the rain.

 

[jonesg]

Re: still stumped. 1989 175GT

finally got to idle rough, will rev in neutral, but bog immediately in gear.

carbs spot, less, timing right on, link n sinced. spark atleast 1/2 inch with tester, no change when pulling spark plug wire.

i am at my wits end with this thing. vro still connected. could it be over oiling and fouling out?

I think I would try spraying a bit of fuel into the carbs when it bogs under load,

or a timing light to see if its dropping spark under load.
Those little neon spark indicators would neat for this.

Both are easier than pulling the flywheel.

 

[ezeke]

Re: still stumped. 1989 175GT

Ezeke, I thought if the magnets move it throws timing out to the point where they won't run, they backfire and act up?

Correct, but how bad the misfire is depends on how far they move.

 

[capngregorus]

Re: still stumped. 1989 175GT

I still think it could be a fuelling issue.. given the time ive spent swearing the one i have.