1989 Evinrude 50HP bogs down

[Bagseye]

First a little background. one of the piston rods came loose from the crank, lost needle bearing, and scored the cylinder. I took the engine apart honed the cylinder and installed a used piston and rings. I have 100 PSI compression on both cylinders. I removed the VRO and installed a regular fuel pump on the side of the motor block where a plug was and installed a plug where the VRO pulse tube connection was on the block. When I first tried to run the motor I found the top carburetor float stuck open and flooding the engine. I fixed this and cleaned both carbs and was able to get the motor running good on muffs.IT ran good at home so I thought it was good to go for a ride.
After starting the motor in the lake and moving the remote control to engage the prop the engine just bogs and dies. I can restart the motor and manually move the carb linkage to throttle the engine up and down and it revs fine.I have tried to adjust the idle screw a little more open and closed but nothing I've tried seems to work. My question is could the compression be too low for the motor not to run when the exhaust back pressure is higher in the lake? Or could there be a problem with the gasket between the motor and lower end? Or could there be an issue with high altitude 8000' and running stock jets? The boat worked fine before the engine sized so I don't think that's it. I have good spark so I think its a fuel issue.
So I guess my question is my motor compression too low for the motor to work in the lake?

 

[racerone]

Did you have to replace the crankshaft ?

 

[Bagseye]

No.

 

[juno pierrat]

just a little more background! " one of the piston rods came loose from the crank, lost needle bearing, and scored the cylinder" wow so you've had the case apart, pistons out, the whole thing apart? got a manual?

 

[kbait]

Did it run fine at 8000’ before teardown?

 

[Bagseye]

Yes I split the case and replaced the piston and put it all back together. It ran fine before at 8000' until the rod started coming loose and then it started acting up and would only run using the priming bulb since the pulsing vacuum wasn't working the VRO pump properly. No manual and no local shops that did rebuilds or boring of cylinders, so I just honed it and used google to get info.

 

[juno pierrat]

more info. New gaskets during rebuild? Torqued bearings, rods , head, ect, to specs? compression maybe low, 87"motors were in the 140+ range, does spark jump 7/16in. gap in open air tester? Not getting any warm and fuzzes so far.

 

[Bagseye]

Just split the case and used silicone to reseal the case. Made a gasket for the motor to lower end exhaust connection. All torqued to spec. Spark jumps the air gap. Could 1 year old fuel or too high of oil mixture cause this issue? Thought I'd ask questions on forum before I towed it 100 miles and pay $125 to have a repair shop tell me the compression was too low.

 

[racerone]

Silicone is the wrong stuff to seal the case !-----I believe you need to revisit this crankcase re-sealing work !----

 

[Bagseye]

Sorry I was referencing the motor to lower end seal. I used a locktite type of seal on the engine split case. Can't remember what number it was but was something recommended as a replacement to the OMC stuff.

 

[juno pierrat]

i,d try the dreaded "sync-n-link" carb adjustments, on u-tube, check "Brandons garage " there's a factory video on carb adjustments for your motor

 

[Bagseye]

Yes I did that according to the OMC video he had posted on his site.

 

[juno pierrat]

year old fuel may have gummed carbs again, clean again, with rebuild kit, small wire thru all passages and jets, remove core plug, very small holes under it. during disassembly, did you notice any dark goo under flywheel by coils or power pack?
back to one of first post questions, don't know about power head to mid section gasket
while idling do a quick "drop test", i'm guessing at this point

 

[Bagseye]

No goo under coils or power pack. By drop test do you mean pull a plug wires? Did that and no difference motor kept running. I will take carbs apart and clean again and see what happens.

 

[Bagseye]

Sorry for the late post but what I did find out is that the woodruff key on the flywheel was broken and was the cause of all my problems. Replaced the key and the motor ran great on the lake. The other problem I had was a stuck open thermostat which was causing all kinds of black goo to run out of the lower end after operation. After I changed the stat the black goo discharge went away.

 

[Crosbyman]

great news… see patience brings joy…