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Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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87 mariner 115 6 cylinder doesn't want to idle, fouls plugs,

Customer Question

87 mariner 115 6 cylinder doesn't want to idle, fouls plugs, dies when put into gear
Submitted: 2 years ago.
Category: Boat
Expert:  Jeff G. replied 2 years ago.
Have you done a spark and compression test?What is the engine history the last few months?When was the last time it ran properly?
Customer: replied 2 years ago.
Checked spark. Good on all cylinders. Compression test good on all but couldn't get a good seal on the bottom cylinder with either of my compression testers, so that one is still up in the air.
I've only had it about a month so don't know a whole lot about it.
Expert:  Jeff G. replied 2 years ago.
Sounds like the carbs may be gummed up.In the front bottom of each carb is a 7/16" hex plug. Put some paper towels under the carbs and remove the plugs with the fuel line disconnected. If the inside of the plugs are discolored, any gum or varnish, then the carbs will need to come apart for a through cleaning. I suspect the idle tube in one or more carbs is dirty and possibly a jet as well.Check this and post back.
Customer: replied 2 years ago.
I have pulled those plugs and any other ones i could find and sprayed through everything with carb cleaner. Didn't really seem to have any varnish or discoloration but will do this again and get the jets out for a thorough inspectuin
Expert:  Jeff G. replied 2 years ago.
Don't just spray carb cleaner, you won't do much. The idle tube is very narrow and comes down from the top. I would recommend pulling the three carbs, get a carb gasket kit, inexpensive and thoroughly clean the carbs. Before removing the idle mixture screw turn it in and count the turns to see where it was set. Then take it out.Those carbs work good when spotless. But are prone to fouling if any old gas was left in them.
Customer: replied 2 years ago.
Ok will do that while I'm waiting on the stator. Just noticed the 2 yellow wires off the stator are missing insulation and have quite a bit of corrosion
Expert:  Jeff G. replied 2 years ago.
You are ordering a new stator? Good. Anything with bad insulation needs replacing.
Customer: replied 2 years ago.
Yep. Know the best place to order from to get it to me fast?
Expert:  Jeff G. replied 2 years ago.
You may want to check locally. For discount pricing try at you can get express delivery, they sell oem parts. I prefer the CDI Electronics parts for that engine though. Basically a toss up.

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