1988 yamaha 50 pro, losing power.

[jakelogsdon]

I was on the way to the duck blind this morning and about 10 minutes into the boat ride, the motor starting powering down. It was exactly like i was slowly letting off the throttle (no missing or spitting or sputtering at all) after it slowed to an idle with the throttle still wide open, I killed the motor to check and make sure there wasn't something wrapped up in the prop. I then just did a quick look over to make sure everything was in order and it wasn't something obvious. I started it back up and tried to run again, didn't get over 5 mph! I tried to pump the fuel bulb while under power with no results. I tried bumping and holding the choke with no positive results. Any help would be greatly appreciated!

 

[99yam40]

Re: 1988 yamaha 50 pro, losing power.

Check compression and spark, then the timing, if all that is good then it has to be in the fuel/air ratio or your throttle cable broke or came loose

 

[jakelogsdon]

Re: 1988 yamaha 50 pro, losing power.

Thanks for the reply, After i posted this thread i was going to check the spark. When I pulled the top plug the gap was almost completely closed. I looked inside the top cylinder with a flashlight and all looked good. Did a compression test and showed 130 psi on all cylinders. Next i took one of the good plugs and put it in the top and turned the motor over for several seconds and pulled the plug back out and it was fine. I guess the next step is to go run the boat and see what happens. I'm still confused as to how that plug got jacked up

 

[BWarrior]

Re: 1988 yamaha 50 pro, losing power.

I will ask do you know where on this motor the fuses are located because i was using the trim and i heard a quick and faint zzt noise and now the trim doesnt work and when you turn the key for the electric start i get nothing, any help is apreciated

 

[99yam40]

Re: 1988 yamaha 50 pro, losing power.

B read the top info on posting and then start your own thread on your motor.

Check your battery cable connections

 

[g-unit]

Re: 1988 yamaha 50 pro, losing power.

If anyone could help diagnos the problems i,m having with 50hp yamaha pro 1988 .It runs fine at idle but loses power when under load.Bogs down when i put into gear and travel Any suggestions on what the problems could be and is there a diagnostic and maintenance manual available

 

[99yam40]

Re: 1988 yamaha 50 pro, losing power.

g
read the info on the top posting about posting on old threads and then start your own thread on your motor.
Sounds like fuel/ carb problems

 

[g-unit]

Re: 1988 yamaha 50 pro, losing power.

did you ever solve your problem with your yamaha pro 50 .I,m having the same problem with mine do you have an idea what the problems might be .any info would be much appreciated ty