Motor lost power

[crownroyal]

Took boat out yesterday. Its a 1988 60 hp Johnson. Ran great,but after running WOT for about 6 minutes the motor died like it was out of gas . It restarted fine but wouldnt go faster than idle speed afterwards. Sitting in neutral it would rev up fine.Came home and took carbs off,they all looked fine. This is the 2nd time this has happened . Im thinking its the powerpack... Any suggestions??? Thanks

 

[rolmops]

Re: Motor lost power

Don't these engines have an emergency mode when they overheat? When they go into this mode the engine will develop enough thrust to get you back to the dock,but will protect itself from overheating <br />You should double check on that and see if there is anything wrong with your cooling water system.

 

[crownroyal]

Re: Motor lost power

It has a new waterpump in it and no horn went off

 

[Solittle]

Re: Motor lost power

crownroyal - I think you are on the right track with the carbs. They may look fine but have a bit of crud inside. Sugggest that you dissemble, soak, blow out with compressed air and put in new carb kits.<br /><br />rolmops - a big congrats on number 1,000. Don't think the SLOW mode was on engines this far back. My 87s don't have it.

 

[crownroyal]

Re: Motor lost power

Ill keep you all updated. I noticed 2 of the carbs the float level was off. Im taking it out tomorrow morning and let you know how it runs. Whats got me puzzled is the bowls of the carbs looked fine with no trash found. Hope the float levels were the problem but im still thinking its electrical.

 

[crownroyal]

Re: Motor lost power

Well took the boat out today. Ran fine like it always did for 1st 5 minutes then died and wouldnt crank like it was locked up. Brought it home and did a compreesion test again and found the problem. Top cylinder 0 and bottom 2 145 to 150. SO its gotta go to the hospital. Whats funny is last week the top cylinder was lowwr that the bottom 2 but it was about 40 lbs lower than the other 2 then. took spark plug out and had metal shavings around it so its looks like a ring busted.

 

[Dhadley]

Re: Motor lost power

Which spark plugs are you using?<br /><br />The damaged piston is the effect. We need to find and correct the cause. Truthfully its the middle cylinder that usually gets damaged on that style motor. <br /><br />Let us know about the plugs.

 

[crownroyal]

Re: Motor lost power

Dhadley...its got Champion L77 JC4 plugs in it. IS that the right plugs or should i be using others? Im going to get the guy to go thru the whole engine while he has it apart. Hopefully thats all thats wrong is a piston or ring.<br /><br />I havent had the boat long but the guy i bought it off of replaced the VRO pump on it with a regular fuel pump when he had it. It never did run right when he had it so i believe the damage was done with the VRO pump not working before he bought it

 

[Dhadley]

Re: Motor lost power

Thats a good choice on plugs. If it never did run right since you had it the damage could very well have been done before as you suspect.<br /><br />Keep us informed and good luck!

 

[crownroyal]

Re: Motor lost power

Update...Got motor to my buddy that works on boats. Top piston was definitely gone with a chunk out of it but it just scratched the cylinder some.Hes going to bore it out and replace all 3 pistons plus rings. 900 bucks i dont think is a bad price. Ive got a manual and it dont look like its a real tough job to rebuild if you have a little mechanical ability but ive never done it before ,id like to find an old engine and just practice on it first before i mess with my main engine.

 

[Dhadley]

Re: Motor lost power

If the top edge of the piston by the exhaust port is whats missing, we need to figure out what caused that.

 

[crownroyal]

Re: Motor lost power

Dhadley,thats what was missing. You think if it wasnt getting oil from the VRO pump that would cause it? The VRO pump has since been replaced with a regular fuel pump and mixing the oil with the gas.

 

[Dhadley]

Re: Motor lost power

If it wasnt getting oil the skirts would show the most damage.<br /><br />If what youre seeing looks like a piece of the piston broke off, thats most likely related to electrical. Most folks think it was just a defective piston that a piece fell off of.

 

[crownroyal]

Re: Motor lost power

Electrical?? Like a bad powerpack or what?

 

[Dhadley]

Re: Motor lost power

Could be related to a powerpack, or a timer base or the flywheel or even a coil. Your mechanic will need to check it out so we dont run into the same thing later.<br /><br />If it still runs now (if its not too far taken apart), this would be a good time to run the tests to locate the cause.

 

[crownroyal]

Re: Motor lost power

Got motor back today after being rebuilt. Had to replace all 3 pistons and rings. The mechanic said it looked like it was running a little lean on oil with the busted #1 piston and the other 2 were scortched. Took it out and it ran pretty good. Havent got down on it yet ,til i break it in running 25 to 1 oil. But the problem is solved when you take off and have to prime the choke to get it to take off,just wasnt getting enough compression on top cylinder. Running penzoil synthetic tw-3 oil. Mechanic said thats a good oil and its better to have more than less on a 2 cycle engine. Thanks to everyone on this board giving me advice and 1 thing ive learned is to check the compression if you think everything else is ok.