Help. '77 Evinrude 55hp

[GatorRx]

First post, here we go.

I'm having a heck of a time trying to get this engine running properly. It idles ok in the water and out of water on muffs. When I put it into gear and try to accelerate it wants to bog down and die. By fiddling with the throttle and very slowly increasing it I can get it past the point where it wants to die and get up to full throttle.

The issue I have found is that the engine will not idle on the top cylinder unless I am squirting gas into the top carb. It will idle on the bottom cylinder (roughly) without squirting gas into the carb. I can get it to run on the top cylinder if i get the revs up a bit though. To try and figure this out I bought a service manual and have looked on this and other forums, here are the steps I have tried so far in no particular order.

-Cleaned and rebuilt both carbs (cleaned top carb twice)
-New spark plugs
-Checked spark (good on top and bottom)
-Checked compression good (120psi on top and bottom)
-Replaced fuel pump
-Decarbed engine with Seafoam
-Checked timing
-Verified that throttle butterflies are opening and closing correctly
-Applied some heavy grease on the outside of top carb body at the point where throttle linkage enters (thinking possible air leak)

Is the top carb the culprit and I need to replace it? Not sure what I should look at and do next.

 

[NicoPags]

in due time, actual pros will have some solid suggestions for you. How does the choke solenoid act on the motor. Sounds like a choking/air issue. When you did the carb rebuild, did you remove/inspect the high speed orifice behind the drain plug? Did you do a cleaning on the air silencer? could be blockage creating a choke on scenario

 

[racerone]

There is not much that can go wrong with these carburetors.----Not sure why anyone would need to replace a complete carburetor.

 

[GatorRx]

in due time, actual pros will have some solid suggestions for you. How does the choke solenoid act on the motor. Sounds like a choking/air issue. When you did the carb rebuild, did you remove/inspect the high speed orifice behind the drain plug? Did you do a cleaning on the air silencer? could be blockage creating a choke on scenario

I pulled out and cleaned both jets on the carb and soaked the whole thing overnight in cleaning solution then blew everything with the air compressor. The choke solenoid seems to work fine. The butterflies are open unless I hold the key in and the air silencer is clean as well.

There is not much that can go wrong with these carburetors.----Not sure why anyone would need to replace a complete carburetor.

I definitely don't want a new carburetor. What should I check into next?

 

[GatorRx]

We took it out to the lake yesterday afternoon, put it into the water and I put it through its paces. It seemed to be running great. Idled in gear, forward and reverse, and the throttle response was good. We went back and forth several times testing and everything seemed great. We stopped to try and catch a few fish and when I went to crank it back up and move spots the problem reappeared. Was difficult to get started and did not want any throttle at all.

Today I'm going to try and bring it back out to the lake and also bring along the spark and compression tester and see if everything is ok after it is heat soaked.

 

[GatorRx]

No spark on bottom cylinder after getting to operating temp.