Bypass Cover Leaking Johnson 115hp V4 Gasket Sealer

[dngbt5]

I have a leaking bypass covers only on starboard side of my rebuilt 1983 Johnson 115hp V4. Told it was a rebuilt 85 however found most parts to be from an 83. Serial number and model # Badges have been removed from block and mounting bracket.

I have tried ordering and replacing the gaskets, adding permatex type 1 sealer, Gasoila PLS2 sealer, making my own gaskets from rubber/fiber gasket material. I also ordered a used set of bypass covers and replaced the two leaking covers. They seemed very straight. I even very lightly sanded the engine side to remove visible scratches left by someone removing old gasket material, I only did this as nothing before this worked?

I Have finally got the gasket to quit leaking air into the fuel line (seen through visible filter) after warm up, but it is still leaking/spitting at start up. Could the aluminum be warming up and expanding and sealing better. I have not been able to watch it run at WOT to be sure it is not leaking I just have noticed the fuel filter is not showing air and the bulb is staying hard. I am worried the two Leaking cylinders Starboard side could still be running lean?

I just ordered permatex permashield hoping it will help work. Is there a better gasket sealer? Should I sand more on the engine as it is the only thing that has seemed to make a difference? What would cause this leak besides non smooth surfaces? too much fuel maybe? Also what is the Correct Torque for the Bypass Covers on this year make and model.

My Spark plugs all look good as do the Cylinder walls, Pistons and rings. Could this be a serious problem? Please help.

 

[Bosunsmate]

if you havent yet, run a straight line ruler along each edge for starters. look for any dips under the ruler. Doing it by eye alone doesnt work, you can easily miss a dip without using a straight edge.
you definitely dont want the cylinders running lean, how are you sure they are leaking?

 

[Bosunsmate]

I Have finally got the gasket to quit leaking air into the fuel line (seen through visible filter) after warm up, but it is still leaking/spitting at start up. Could the aluminum be warming up and expanding and sealing better. I have not been able to watch it run at WOT to be sure it is not leaking I just have noticed the fuel filter is not showing air and the bulb is staying hard. I am worried the two Leaking cylinders Starboard side could still be running lean?

.

Im not sure which gasket you mean here.
the fuel pump should have a small gasket between it and the block, you should never be getting air into the fuel pump or the line past it.
the filters always before the fuelpump in my experience but sounds like yours is after the fuel pump
this is the gasket for fuel pump to block, have a look and see if thats where you think its leaking, its only a few dollars to replace
303615 — GASKET,FUEL PUMP

 

[racerone]

The bypass covers close the crankcase.-----They contain crankcase compression.-----Not sure how you come to think that this leads to air leaking into the fuel line at all.

 

[dngbt5]

I did check the covers with a straight line steel ruler and the looked good. I will re check them though. I know they are leaking because I can see them cough fuel and air when starting with the cowl removed (had a friend start)and fuel is building up around and under the bypass covers. Racerone I was just guessing that the leak was getting air into the fuel line because it was the only leak I found. Now that you say that it doesn't make sense to get fuel in my fuel line from this leak but I feel it still needs fixing. The fuel filter I am speaking of in an in line visible filter I installed before the motor so I can see what's happening in the system before the motor. I will disassemble it and make sure I rings are good and it is tight. Thanks for the responses I will look at the covers and maybe do a light sanding on ten also before re installation of the covers.

 

[wayneo99]

I had the same problem on a rebuilt power head from OBR. I swapped the covers so I could have the fuel recirculating system. I had the number 1 cylinder bypass cover leaking. tried several covers and they all seem to not fit correctly. I had 4 or 5 extra and I filed the ends where it goes into the block down and it fir fine. I believe I found one that fit better without modification and I used 2 gaskets to keep it from leaking.

 

[dngbt5]

Wayneo99 thank you I was hoping I want the only one. My new covers I put on the motor seem to fit good/no resistance. Did you file the flange part that meets with the gasket or the part of the cover that goes inside the block (the fins)? When I purchased the two I am using now they came with two more that have the circulation ports, what is the advantage to those and how do they connect? Finally what type of gaskets did you use when you used two together and did you use sealant? Torque?

 

[wayneo99]

file the fins, no sealant, not sure of torque. the recirc system is part of the new motors 1983 and newer i think

 

[dngbt5]

Wayneo99; Thanks again. I actually read a post about a Johnson 9.9 that mentioned doing the same thing. I am guessing the end of the fins must be making contact with the cylinder wall and keeping the cover from fully sealing. Probably the wrong cover for the year of the engine case? I will definitely try that and get back to you thanks Wayneo99 and all others that responded to my post. I really hope this works. From what I have found 5lbs or 60 inch pounds should do the job.