1977 55hp Johnson lower cylinder no fuel?

[59 Sea Coaster]

So I have this engine on my Coaster for now and am having some issues that are baffling me?

Details
Compression 130psi both cylinders
Spark jumps the 7/16' gap both cylinders

Carbs cleaned and fuel pump replaced this past winter

Just now getting around to seeing if the carb/fuel pump work paid off......

Nope same situation as last season.

Starts and runs on one cylinder, upper

If I close the choke plate about 3/4 on the lower cylinder it will come to life and the motor sounds like it should. Snappy and responsive!

This is what led me to think I had a fuel delivery issue and cleaned the carbs and replaced the fuel pump. The carbs were actually quite lean already, impressively clean actually!

I purchased the engine used about two years ago, needed something to power the Thompson while I restored the original 59 Lark Jubilee. Still have not gotten to that project. Just want to enjoy the boat once in a while in the summer during the week when the visitors are back in their own state!

Anything else I should be looking for?

Thanks in advance for any suggestion or enlightenment!.

Joe

 

[iggyw1]

I am far from a motor expert, however, that 30 of compression on both cylinders is nowhere near what it should be. I am surprised that the motor is starting at all with that compression. To me, it surely sounds as though you have a blown head gasket at the least.

 

[racerone]

The 30 PSI is a huge concern.----Could be a blown head gasket !

 

[59 Sea Coaster]

Shoot, late night typo 130PSI sorry

 

[oldboat1]

typo maybe (130?) If not, try another tester or technique (or both). Plugs out, crank until the needle stops.

Nice boat. (Know what you mean with the comment about out-of-state visitors this year.)

[ed. oops. PSI corrected in the meantime]

 

[oldboat1]

Might open up the lower screw plug and run a piece of soft wire through the jet, follow with a squirt of carb cleaner using the plastic nozzle.

 

[flyingscott]

Maybe take the lower carb off again and re-clean. Did you soak it sounds like the idle circuit is plugged?

 

[iggyw1]

Good point by flyingscott to soak the carb. I rebuilt my carb last spring & did not soak it, had a problem trolling all last season. This spring, I rebuilt the carb again, but this time I soaked it overnight in a carb cleaning solvent, and it is running like new now. I found two bad gaskets in the carb but I think by soaking it, it cleaned out all the ports & nooks & crannies in the carb. & helped it out in a BIG way.

 

[59 Sea Coaster]

Could the carbs be switched? Upper to lower/lower to upper? I think if I swapped the bowls so the top one would still feed the bottom it should work? That would confirm a carb issue and not a seal or compression issue.......

 

[racerone]

Each carburetor feeds one cylinder.----Except for a small balance passage way.

 

[59 Sea Coaster]

Racerone, the top carb has the main fuel line running into it and out of that carb to the lower one. It did not appear they could be swapped.

Regardless, I pulled the lower back off and re-cleaned the low and high speed orifices reinstalled and on the muffs it is running well on both cylinders! Appears I may have missed something........ that happens in March sometimes I guess.

I will try to get to the water today before most of IL gets here and try some wet testing!

Will update with results.

Joe