Fuel mix seeping from front of v-4 crossflow?

[rothfm]

Couple questions on my latest "build-up". 1987 Johnson 90hp. Good spark, 120lbs on all 4. Timing set good. This was a complete disassemble, rings, cleaning, paint-job and anything that needed attention.

1) Somewhat rough running at idle, and at elevated RPM's. No sneezing-just a bit shakey rough. Lots of smoking and very wet plugs. I Found fresh fuel seeping from front of carbs-I believe both. I will dig into them again.....I also had the butterfly's very slightly open at idle too, now corrected....But can this bowl overfill, really cause the rough running, and extra smoke? I'm thinking so.

Pic attached with a pointer of carb tubes where fuel is draining from. Current stand puts the motor at a slight angle under 15 degrees.

2) Power-head to adapter small exhaust leak....fresh everything (all apart, new gasket, bolts etc). I put on dry. Are double gaskets ever done here? Or I'm inclined to use a sealant when i pull the head again. leak is at the rear stbd corner where it meets the t-stat housing area. (all torqued to spec).

Thanks

 

[emdsapmgr]

Crossflows tend to overfuel at idle. You will see black wet plugs while idling. That's normal. Fuel leaking from the front of the carbs is common when the engine is off, and the engine is tilted upward. Common to get a few drips from the carb throats. Not common when idling/running. Both carb butterflys must be closed a idle. Otherwise other jets start to supply fuel and you can get erratic rpm's and odd running. OMC has used two powerhead exhaust gaskets over the years. A simple, paper gasket is a sure leaker. The upgraded gasket is a paper core, with a sort of metal coating on both sides. That is the only one that will stand up to exhaust gas.

 

[rothfm]

Thanks EMD.....yes, The small "flow" or seeping was with engine off, after running it awhile...And as I was cranking (with plug wires off) so I could watch. It was more then a few drips however. Even thought I was very careful with the Carb rebuilds, I was thinking the bowls were overfilling as the smoke was heavy also, like it was rich. The roughness was still present with some RPM applied. I might omit the old VRO (fuel only) with a new Std style fuel pump (conversion).

Is there a way to test Crankcase compression for pulses to the fuel pump. I dont believe I have any case seal issues. At least not visible.

That gasket...Rgggg, done these many times and seldom have a good seal first attempt. My gasket was not paper thin, but sort of thicker and didnt seem like a Coated variety. Going to Pull the head again to look, May try Avaition Gasket sealer with it. Or Maybe get a current BRP branded

.

 

[emdsapmgr]

One other thing regarding excess smoke when the engine is just started. If the engine was tilted up when last shut off. Some amount of fuel/oil will run down the front of the carbs. That small excess will then accumulate at the bottom of the airbox cover. When next started , the engine will scavenge that excess oil/fuel. Suck it from the airbox through the airbox drain hose-back into the bottom cylinder-where that excess is burned off. You will find that after just starting, that the burning of this excess will cause a temporary smokiness to the exhaust. After a minute or so, the exhaust smokiness should clear out and you will be ok the rest of the day. (or until you tilt the engine up again-such as if you are fishing.)