Motor Killing

[BlueFins]

I had a older Mercury motor winterized last winter and hasnt run good since. I troll slow and after a while it keeps acting like it wants to kill and does. They put new spark plugs in and also said it never had a thermostat in it so they put it in. Where is the thermostat and how would I take it out?

[eurolarva]

How old is the gas? I would maybe get a second opinion on the spark plugs. I have had mine replaced by marinas and they must have so many cross reference ones they never get them right. I doubt the thermostat is the problem however post your model number and make.

[BlueFins]

1987 9.9hp Mercury. My book states that it should have Champion L82yc but I know most Mercury dealers have went to Ngk but they had them in once and I couldnt get it started at all sometimes. They actually thought I was crazy for putting in L82yc cause there book had L78yc in Champions and it has a different gap. I had them put in the L82yc and thats what in it. Always put new gas and oil in and empty it at the end of the year.

[marine_man]

Quote:

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and empty it at the end of the year.

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Can you explain this a little further - you empty the tank, you drain the carb bowls, you run the motor out of gas

Also, can you explain the problem a little more - does it only have problems at idle?

marine_man

[BlueFins]

I empty the tank about once a month and at the end of the year. It kills after a while of trolling slow.

[marine_man]

When you empty the tank are you running the carb dry, running fuel stablizer through it before the end of the season or draining the bowls at the end of the season? It sort of sounds like some junk stuck in the low speed jet.

marine_man

[BlueFins]

How do you drain the bowls and run the carb dry? What should I do to get whats stuck in there out? I seen theres a fuel filter by the motor, how do I take it apart to look at it?

[eurolarva]

If you run an outboard till it is out of gas you run lean causing a lack of lubrication in the motor. If you run it dry to winterize it you should be spraying fogging oil into the carb while it is running.

To answer your question you will have to remove the carb and clean it. If you do decide to do that it is worth buying a carb kit for the motor. When cleaning use carb cleaner, a thin wire and compressed air and clean out all areas and holes you can see. Be careful around the jets with the wire because they are soft metal and you dont want to ream them out.

[marine_man]

Based on your response I'd say a good carb cleaning is in order - the gas that stays in the carbs over the winter turns to a varnishly sludge (unless you've been using fuel stabalizer) and small chunks of it float around in the bowl, in this case clogging your slow speed jet.

I would strongly reccomend using a fuel stabalizer in each tank of gas you use - or at the very least, if / when you plan on leaving the motor sit for a month or more. Add the stabalizer and run the motor for a while to get the stabalized gas in the carbs and you should be able to avoid this problem. That's the easiest and cheapest way to do it in my opinion anyway.

marine_man