Anyone Recognize This Gooey Stuff?

[bobgritz]

When I separated the gearcase to change my water pump I was greeted by this gooey mess (see pic).

I was changing water pump due to cylinder heads running hotter than usual and very little water coming out of discharge port.

Not sure if it's related but the engine dies when I pull the lower cylinder's spark plug wire but there's no reaction when the top spark plug wire is pulled even though it passed a 1/2" spark test and it is getting plenty of gas (plug is wet). Could this goo be some kind of blow-by from the crankcase of that upper cylinder) which is also causing it to not contribute any power. Both cylinders check in at 115 lbs.

 

[BonairII]

Re: Anyone Recognize This Gooey Stuff?

That goo is unspent fuel, I believe. It's nothing to worry about.

Your top cylinder prob has spark that is suspect. The quality of the spark may be degrading after engine gets warm. If you're plug is wet with fuel, then it's def not sparking correctly.

Not sure what motor you have, but if you can....swap coils and see if the prob follows the coil.

 

[bobgritz]

Re: Anyone Recognize This Gooey Stuff?

So BonairII, I guess you're saying that unspent fuel is being exhausted down the exhaust tube where it is bubbling with water (in the lower housing) then churning itself into this frothy mix.

That makes sense since that top cylinder is not burning up it's share of fuel.

When it does start, you must immediately twist the grip and raise the rpms to high speed for both cylinders to work. But as soon as it idles down, it sputters then stalls. If it does stall, you must crank the heck out of it (open throttle/no choke) to get it to restart.

 

[BonairII]

Re: Anyone Recognize This Gooey Stuff?

I asked the same question awhile back cause I had the same goo coming from my '67 Johnson(gas hog). Have you cleaned your carbs and set your floats recently?

Not sure if you're not getting enough fuel or getting too much(flooding).

Inspect all fuel lines and tighten all connections.If any fuel line is old and/or suspect whatsoever....replace it. Old line will degrade and throw crap into your carbs,

 

[bobgritz]

Re: Anyone Recognize This Gooey Stuff?

I have rebuilt carb, swapped coils & powerpack, rebuilt fuel pump, and bought new spark plugs but top cylinder still has no effect when wire is pulled. There's no spitting back through carb so I don't think it's the reed valves. BTW, it's a 1983 15hp.

 

[AlTn]

Re: Anyone Recognize This Gooey Stuff?

try an inductive timing light while the motor is running. Is the flash the same for the top and bottom cylinder?...if so..you must have something entering the cylinder causing the ignition to fail. Most likely culprit is water from 1. head gasket 2. exhaust cover gasket 3. crack in the liner or head, of these #1 is most likely followed by #2 , #3 is a very distant third.

By "swapped coils and pp" do you mean replaced with new?

Does the fuel pump mount to the upper or lower part of the by-pass cover? If it mounts to the upper, it's possible it's leaking fuel into that cylinder causing the mixture to be too rich to burn.

 

[bobgritz]

Re: Anyone Recognize This Gooey Stuff?

I already pulled the head. When I went to buy a new head gasket, I showed it to a Johnson mechanic who said there was absolutely no carbon buildup and that the water passageways were all in very very good condition. Compression was 110 per cylinder prior to removal and rose to 115 each after replacing with new head gasket. I think we need to rule out the head as the problem due to good compression, condition, etc.

AITn, you mentioned the "exhaust cover gasket" which got me thinking.

I always had a nice steady stream of water out the overflow opening (p-hole) but now it is spotty and quite hot and the power head is extremely hot whereas before you could put your hand on it. This was why I pulled the bottom end and checked the water pump (which appears to be in normal condition with no obvious signs of wear). What if ... there is a crack or break in either the exhaust cover and/or exhaust cover gasket? Wouldn't this tend to disrupt the water flow through the passageways perhaps even forcing hot water to travel backwards within the system? And, this might also explain the minimal hot p-hole water and perhaps even explain the heavy gooey crap accumulating at the base of the exhaust casing!

Could it also explain why the uppermost cylinder is not contributing to the overall running of the motor??? If the exhaust cover gasket or exhaust cover has an imperfection, perhaps the exhaust stroke of the good (bottom) piston is interfering with the operation of the upper cylinder. Or perhaps the ineffective upper cylinder is simply not able to complete its exhaust stroke.

BTW, you asked about swapped coils and pp: I did swap the upper coil with the lower coil but the upper cylinder still had no effect when its spark plug was pulled. I have a parts-motor and tried a coil off it with no change. I swapped the powerpack with the parts-motor's pp with no change and although it was not new, it's doubtful that it would also have exactly the same effect as the original. I think the exhaust theory has the most merit at the moment.

I've spent so much time on this engine and although I should probably take it to a mechanic, it has become personal. Come on folks, let's figure this one out. Comments Welcomed!

 

[ward cleaver]

Re: Anyone Recognize This Gooey Stuff?

Did you test the continuity from coil to the spark plug boot? As long as you are in there you might as well change out both the wires and the boots.

 

[bobgritz]

Re: Anyone Recognize This Gooey Stuff?

Yeah ... I switched top wire with bottom wire ... same bad result (nothing happens when I pull top wire but engines stalls when I pull bottom wire).

 

[BonairII]

Re: Anyone Recognize This Gooey Stuff?

If you have changed the coils and powerpack etc....maybe a problem within the stator?

 

[bobgritz]

Re: Anyone Recognize This Gooey Stuff?

I'm unclear as to the exact function of the stator and wonder if it could be causing be a timing problem.

Everything that I read says that if you have a CDI ignition system and if you're getting a strong spark (passed 1/2" spark test) then you can discount the magneto area. However, even though there is a strong spark what determines the timing of that strong spark. In other words, which electrical component controls the timing of the spark?

It seems ironic since both cylinders work fine at high rpm's but at slow speed the upper cylinder has no effect?

 

[AlTn]

Re: Anyone Recognize This Gooey Stuff?

the timing sensor or "trigger"...on that engine, nothing under the flywheel will affect only one cylinder < with the exception on a bad wire >...the stator comes into play only if you have electric start and again, on that model, it's just 2 charge coils that are separate from the power coil for the pp

 

[BonairII]

Re: Anyone Recognize This Gooey Stuff?

It seems ironic since both cylinders work fine at high rpm's but at slow speed the upper cylinder has no effect?

I'm just spitballin' here, so take it FWIW

Maybe at higher RPMS the motor is able to overcome a fuel delivery issue and is able to get enough fuel to the so-called 'bad' cylinder. Are all fuel lines in good shape and connections tight?

Is it possible that the bad cylinder just doesn't have enough draw to get enough fuel into the cyl at low rpm?