1985(?) 50hp Outboard Losing Power/Dying

[TheDeepFreese]

I believe I have a 1985 50hp outboard that will fire up and purr like a kitten and get out into the lakes and run like a dream for 10-15 minutes and then will begin to lose power even at full throttle. This will progress on until the motor actually dies. The last time I decreased throttle once it started to lose power and was able to make it back to the dock under power. I just replaced the ignition module and have replaced a few of the wires connecting the module (due to age/wear). Was curious if anybody out there had experienced anything similar or had any suggestions for what it could possibly be? Any help would be greatly appreciated as a running/functional boat will make the wife much happier than a husband spending all his time confusing himself looking at a boat motor!

 

[fastjeff]

Sounds like fuel starvation. Is the vent open on the tank? If so, I'd look into rebuilding the fuel pump.

Jeff

 

[papyson]

is the alarm working on the boat?you could be overheating...you could be starving for gas....the first two things that should be checked are compression and fire..fire should jump 7/16 inch on a tester...tester is available at any good auto parts store cheap...after those two checks your decision is it a fuel or fire problem?i use and inductive timing light for this..when its failing see if all the cylinders are firing correctly..if this is ok then address a fuel problem..will pumping the bulb help?is the gas new and the tank well vented?are there any indications of a fuel or air leak..will the bulb pump up hard and hold it before you start the motor?(once the motor is up and running the bulb will not be hard) ....a word of caution here...if it is a fuel starvation issue or an overheating issue you will burn a piston if its is not fixed asap...

 

[TheDeepFreese]

Thanks for the replies both of you! I had thought it could be a gas thing as well but you can still hear fuel running through the line when priming the bulb so I don't think it's starving for fuel but will double check again. All the plugs are firing and hopefully I'll be able to check the compression on the weekend to see if there's an issue with that. If there is compression issues, would that mean then new cylinders are required? Overheating the engine is my biggest concern as I don't want to blow a cylinder/heat seize the engine!

is the alarm working on the boat?you could be overheating...you could be starving for gas....the first two things that should be checked are compression and fire..fire should jump 7/16 inch on a tester...tester is available at any good auto parts store cheap...after those two checks your decision is it a fuel or fire problem?i use and inductive timing light for this..when its failing see if all the cylinders are firing correctly..if this is ok then address a fuel problem..will pumping the bulb help?is the gas new and the tank well vented?are there any indications of a fuel or air leak..will the bulb pump up hard and hold it before you start the motor?(once the motor is up and running the bulb will not be hard) ....a word of caution here...if it is a fuel starvation issue or an overheating issue you will burn a piston if its is not fixed asap...