'95 Twin Johnson 175's

[FreeBeeTony]

I have a pair of subject motors. They have decent compression across all 12 cylinders, 95-105. Thermostats replaced last spring along w/ rebuilding all 12 carbs and new plugs. VRO's are still in use. For the most part the motors run well except the port shows an oily residue at the exhaust....see pic.
Any opinions/thoughrs? OK to run as is?

 

[Chris1956]

Is the port engine smoking more than the stb?
The OMS pump on those motors will mix more oil if there is an air leak in the gasoline line.

Are all the port spark plugs the same color as the stb ones? If not the carbs may need attention.

 

[FreeBeeTony]

Is the port engine smoking more than the stb?
The OMS pump on those motors will mix more oil if there is an air leak in the gasoline line.

Are all the port spark plugs the same color as the stb ones? If not the carbs may need attention.

I pulled the plugs at the end of last season when I checked the compression......did not notice anything strange.

I understand the oil side of these pumps are not serviceable.......guess all I can check is for an air leak on the gas side. After the pump of before........when I pump the bulb up I don't see any leaks.

 

[Chris1956]

Air can leak into the gasoline line, even though gasoline doesn't leak out. I would look for an air leak at the main strainer under the airbox, followed by any filters and metal fittings on the gas line. The main strainer has an oring plus a gasket. make sure both seal.

Another potential source of oil is the recirculation system. Do you see pooled oil under the carbs? There are some vacuum lines that have excess fuel in them, if they leak, the gasoline will evaporate leaving residual oil.

 

[racerone]

The oil side can be taken apart and inspected.----Consists of a wee piston with an o-ring on it.