1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

This started a few weeks ago ,,,,, My son and I were after smallies with air temps in the 40's I started the boat at the ramp and let it warm up a good 5 min. then we took off after 2-3 miles up river while WOT the engine just shut down and the engine kicked up (unlocked). It restarted and we were back under way only to do the same thing after a short distance,, this has happened on 3 trips now. run a bit then bam,,,,,,,,,,,,,shut down,,,,,the engine starts back with a lil' temper and fuss till the next time,,,, Today it happened again and when we returned to the ramp my brother took off the engine cowl and I noticed that the oil tank was full and 6 hours prior it wasn't that high on oil level. I noticed when he shook the boat that the oil was real thin and I knew that it had fuel in the tank at that point, so I spun the oil cap off to verify the oil was now mix'd with gas and sho nuff I now have a engine that shuts down and makes oil ,,,,,,,Any suggestions before I fill it full of quik-crete and send it to the bottom?????? Thanks for any input that may be given.

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

remove the sparkplugs and check for any "beads" of water on them...do the plugs look super clean?....roll each piston up and try to see the top of it through the sparkplug hole...any of them look like they've been steam cleaned?....take and post compression readings for each cylinder....if you'll post the model no. for the engine it'll help to find parts diagrams...

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

And before all this it was just fine ????? or is there some more history that we need to know ???

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

Fuel pump has failed. It is pumping gas back into the oil reservoir.

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

The oil mixing unit has failed and fuel is getting back into it and letting fuel into the oil tank. This was a known prob on these mtrs. The best thing you can do right now is remove the oil mixer and the oil tank and re-plumb the fuel lines coming from fuel pumps and go directly the the carb fuel manifold. Then run 50:1 premix. Hopefully you didn't hurt the p/h but you will find out. You may even want to try a tank or so of 25:1 fuel mix first.

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

Just removed the oiler and tank and reconnected the fuel lines that came from pump unit,,,,,Fix'n to go to the lake and see what happens and go from there,,,Thanks for replies.

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

H2OHunter said:

Just removed the oiler and tank and reconnected the fuel lines that came from pump unit,,,,,Fix'n to go to the lake and see what happens and go from there,,,Thanks for replies.

Click to expand...

Don't forget to pre-mix the fuel

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

What fuel mix did you use ??

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

All is well,,, I ran it with 3 gallons gas and 10oz. of the johnson evinrude oil that I always ran in the oil tank,,,,,I'll run a 50:1 mix and error towards running a tad bit more oil when added,,,,,It ran well, started on 1-2 pull every time and jumps out of the hole. I GOT LUCKY

Re: 1996 25hp 3cyl. dual problems,,,,,,,,,Shuts Down and fuel in oil

Just curious. Did it run longer than the last time before it locked up ?? If it did, you got real lucky.