1975 Johnson, 6 hp, loss of power

[ceugene]

I just purchased a 1975 Johnson 6 hp, it ran great for about 15 min. on the water, then I lost power and was barely able to make it back to the dock what seemed like about one quarter of its power, I took the cover off, and while in neutral, it run and revved up with no problems, but as soon as I put it in gear, the engine bogs down like there is a very hard load on it, and wants to almost stall out. Like the engines is in a bind or something froze up or just too tight. Can anyone have an idea what may cause this?, What would cause it to lose all the power when I put it in gear? Thank you for any help you may be able to share with me.

 

[racerone]

They all wind up in neutral and that means nothing.-----It will do that running on only one cylinder.----For you to check with no money spent.-------Do you have spark on both cylinders that will jump a gap of 1/4" or more ?---------The motor has a seperate ignition system for each cylinder.-------Have you checked compression ?-----A new to you motor should have the waterpump inspected or replaced.

 

[boobie]

Do a cylinder drop test on it and see if it's running on both cylinders or what.

 

[ceugene]

thinks, I checked the spark,and it seems good, The motor was running good prior to it losing power, so I honestly don't think it lost compression, one other thing I think I need to tell you, my fuel tank is an older tank made of steel, and it was exposed to the sun, it did get hot and I had to release pressure out of it a few times prior to using, so my question is this, could the pressure in the gas tank have caused my fuel pump to go bed? Reason I'm saying right before losing power I heard something like a pop f or a snap them I lost the power. But as I think of it, if the pressure was enough to cause the diaphragm in the fuel pump to blow, the pressure in the tank than what it had been enough to keep fuel going to my engine, and keep it running? But not enough to keep it running full throttle?

 

[racerone]

Questions above have not been answered so it is difficult to help here.

 

[Tim Frank]

thinks, I checked the spark,and it seems good, ...., so I honestly don't think it lost compression, one other thing I think I need to tell you, ...

"Spark seems good" and "I don't think it lost compression" are not very useful contributions to effective troubleshooting and aren't going to get you the help that you are looking for.
If the spark "seems" like it will jump a 1/4" gap, and you "think" the compression is in the 70PSI + range and within 5 % on both cylinders, then it "might" be time to check the fuel system.

 

[F_R]

I think it is running on one cylinder. Could be anything from a bad spark plug to an ignition problem to a blown head gasket to water in a cylinder to a tossed connecting rod. Troubleshooting tests are required.

UM,,it does have oil in the lower unit, doesn't it? And in the gas? And water pump is working, right?

 

[ceugene]

Thank you guys, I've been busy checking out all that you guys have suggested, and found some bad results the lower cylinder was not only running, but when I took the spark plug out, it was blowing water out of the lower cylinder while the top cylinder was running okay. The gentleman I purchased the motor from, was nice enough to refund me all my money for the engine. So this issue I would say is closed. I do however really appreciate all the help and suggestions I have received from all you guys at iboats forum. Thanks

 

[racerone]

Sounds like the head gasket was blown.-Compression test would find that !!