1989 Mariner Magnum 150

[Farley]

So up at the cabin last week we ran the boat for 3 days with no issues. On the 4th day we put in $40 gas from one of the resorts and the resort owner said he doesnt know if he has enough, it's the end of his barrel, which I'm asssuming is last seasons gas, could have been older I guess. We get up on plane and go probably 1 mile and we lose power. Motor is now hard starting, the only way to get it to fire is to pull up the high idle switch halfway. Once we got it running again it still didnt have full power, not even enought to get up on plane. So then we took off the cover and found a small gas line that broke off its fitting. We fixed that and got it fired up but still running like its missing. Boys all said it must just be bad gas so you got to burn it all out. At this time it also started beeping when key was on like there was no oil. checkd oil and it was at about half a resivoir. Used the 9.9 to get back, put in 3 new spark plugs on one side of the motor, ran it for a bit, pulled spark plugs and they were all wet, also noticed a lot of fuel comming out of the exhaust. Cleaned spark plugs and put them in other side and ran it, they came out clean. Figured it was the switch that runs the coils on the one side so dropped it off at the marina to get fixed. Got a call that says my #1 and #2 pistons are scorched really bad and its gonna cost $4000 to fix. I dont understand how no spark on one side of the motor equates to scorched pistons, or could it all be related?

[Eelpout08]

Sounds like the bad gas clogged something and made those two cylinders run lean, which would burn up the pistons and then you would not have enough compression to make the fuel burn, which is why the plugs were wet.

Or the broken line on the motor starved those cyl. of fuel or let air in, which would have the same results.

Unfortunatly that isnt good for your pocketbook.

Two stroke motors are really pretty touchy about fuel quality.

Unless you know the mechanic well it may be a good idea to get a second price from someone else.

Good luck, hopefully you can get back on the water soon.

[boatfixer]

Yup! all that and maybe even the poor fuel wouldnt burn completely away causing the cylinders to wash down. Expensive fix no matter what the cause.

You mentioned no spark one bank. Did you check for spark or just figured that because the plugs were wet?

[Farley]

just assumed because the plugs were wet.

We only ran it 1 mile since we put in the crappy gas, can you scortch the pistons that bad in 1 mile of operation? We had close to 1/2 tank of good gas when we bought the $40 of crappy gas. I wonder if that loose gas line had more to do with it than I originaly thought.

I guess my next question would be: Should we go with a 2 stroke or 4 stroke?