Deiseling when fogging

Riley wrote: I used the MMO for fogging a few say it will ruin your engine as it has solvents in it.

Bruce,
All oils have solvents.

I used the MMO for fogging as I've always heard that people used it and that's all I had at the time. I did some research on it yesterday and for fogging, I found many people swear by it, but a few say it will ruin your engine as it has solvents in it. At this point all I know is it makes a nice cloud of sweet smelling smoke.

It's an Indmar 310 carb. Stock Vortec, so I would guess the compression is relatively low. Maybe the fogging oil builds compression? We've owned the boat for 12 years and it never did it until last year. I typically use any aerosol product which is what I used last year. This year I used MMO as that is all I had. The noise that comes out of the top end when dieseling makes me think I'll forego spraying it in the carb next year and spray it in the spark plug holes instead.

Gary, it is early, but I winterized my BIL's boat 3 weeks ago and while it was 90 degrees yesterday, the leaves and acorns have been dropping for 2 weeks. This boat clocked 67 hours this year and won't be getting used again until next year.

Ive never had that happen to me. You must have some dam good compression. I always use an atomizer with straight ATF when i fog. Get a good coat into the engine through the carb whilst running. Once it starts to choke out i hit the air bleeds on the carb on my way out then i kill it with the ignition. I then proceed to coat a lot of the engine with that or wd40. At the same time as this is all happening i am sending antifreeze through the system. So once and done.

One thing not mentioned is - your doing it way too early! Higher air temps = higher intake temps creating a self igniting condition

My problem isn't being able to kill the engine. I actually try not to kill it as I read somewhere, (maybe in the PCM manual) that choking out a 4 stroke engine can actually do harm to the valve train, but I don't want to get into that. This engine, this year and last year dieseled when I turned the key off which seemed pretty strange as it had never happened before. I was wondering if anyone else ever had it happen.

50-50 mix of Marvel and engine oil out of a pump oiler is my favorite for fogging. I have used an aerosol but always go back. I learned the 50-50 way back fogging at Watercraft Sales in the late 60's. The home made will always choke out the engine but as mentioned, it almost takes two cans at once to choke the engine with an aerosol. I feel you get more in the engine with the homemade.

Spray in more fogging spray till it completely chokes out.