New guy with Engine problem

Hi guy's.
Hey I have a question on loss of power. I'm not a big engine guy, and sure as hell not a marine engine type guy. Most of the Marine engine end, is Greek to me.
My wife and I were out fishing {salt} in our 15 foot Livingston, as we started back the engine powder started dropping from 27 mph; while in full throttle. I thought at first we may have been running out of gas, so I stopped and which tanks. I also notice that my Lawrance had gone out. I restarted the engine and throttled back up with, it had very little power; just enough power to push the boat forward (no wake) speed; I turned the Lawrance back on. I called Vessel Assist and was lined back in 3 miles out? On the way in I notices the Lawrance would not turn on again, but the motor would turn over and start at an ideal, die if put into gear.
There?s not smoke, loud metal sounds, not heat, {with that said the number 2 spark plug seemed a little warmer than the others if that means anything} green light was on all the time, water pump was working fine,

The motor is a 1984 Yamaha 40 HP OB 2 cylinder 3 stroke... for the last three years the motor as been great, never had any problems with it. Maintenance is kept up and plugs are change regularly. It?s been a great motor.
Thanks for any help
436

Re: New guy with Engine problem

better check fuel system starting at fuel pick up in tank, connections, primer bulb, quick disconnect on motor, fuel filter, fuel pump, drain each carb, you may have to get carbs removed and cleaned. after you get it back running, install a fuel/water seperator(Walmart $27), really goes a long way towards eliminating fuel related issues. Use Stabil Marine in gas tank all the time. Good Luck!

Re: New guy with Engine problem

Always do a compression check first when having engine problems just to keep from sinking money into an engine that may have a major problem. I know this sounds dumb but did you check and make sure the prop turns ok? No debris? Try squeezing the bulb with it running and see what it does. Good luck.

Re: New guy with Engine problem

sounds like a weak spark to me, you also said your fishfinder went down. what is battery voltage at? your spark and your charging system are tied together under the flywheel. i would check voltage output of alt and coils.

Re: New guy with Engine problem

stylesabu said:

sounds like a weak spark to me, you also said your fishfinder went down. what is battery voltage at? your spark and your charging system are tied together under the flywheel. i would check voltage output of alt and coils.

Click to expand...

I agree u need to check the voltage. A low voltage issue can cause major havac on the equipment and the motor.

Re: New guy with Engine problem

Thanks guy's.... I just had the prop shaft/seal repaired, I hoping that's it. All the other suggestion my yet still be on the table; again thank you all for your suggestions and help.
436

Re: New guy with Engine problem

I am sorry but I do not see how a shaft seal would do you any good for the problems you described. Seals keep water out and oil in the lower unit, not affecting the power of the motor unless the lower unit was starting to lock up from no lubrication and then it would be more than a seal that needs replacing.

Re: New guy with Engine problem

Forget the battery -- it is not needed for the engine to run. The magneto provides ignition once the engine is started. The battery merely runs the starter. It can be stone dead or even disconnected and the engine will still run.