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View Full Version : 1996 Merc 200 XL - Stumbles/Bogs at 3000rpm



aalbert
12-01-2002, 03:15 PM
Was out yesterday, and after about 3 miles of idle speed, and 9 miles of 4400-4800 cruising, my motor started to stumble/bog.

Brought it off plane, and did a cursory visual for anything out of the ordinary, and didn't find anything. Tried to go back on plane, and at 3300-4000rpm, the engine stumbled again. Repeated several times, same story. Tried to maintain just 3000rpm - same story.

Finally limped the 12miles back home at 1100-1200rpm. Replaced the engine mounted fuel filter (didn't note any obstruction in the old one) as well as the fuel/water seperator. Tested the boat with no load, and could free rev to any desired RPM.

I took the boat out again today, and was able to maintain 3400rpm, but a little bit but the motor wasn't happy (boat wasn't on plane yet, so it was having to struggle - only kept it at 3400 for 10 secs or so) and I didn't want to hurt anything more than might have already been done.

Brought it back to idle, killed the motor for half an hour - took a swim to relax, and brought her back in at 1200 rpm or so.

Only other factor that I can think of as of late, is that I gassed up with 30 gallons of fuel yesterday, and I am wondering if it was full of crud....

What are the general thoughts on this? Rebuild carb, start looking for damage to motor with a compression check, or ???

MTCM
12-01-2002, 03:23 PM
May be something in the tank obstructing the pickup inside. Also check for a sticking anti-siphon valve at the fuel tank fitting. To eliminate the fuel tank, try a portable fuel tank temporarily to see if the problem clears up. Just a thought before you tear down the engine.

DaveR
12-01-2002, 06:23 PM
Check your stator (and all the wires - especially where they clear the flywheel), the high side might be bad.

mercrunner
12-01-2002, 07:03 PM
you stated that you had a new load of fuel. If you mix your fuel with the engine you have, you may have picked up an extra shot of oil when you were idleing and running slow and possibly fowled out a plug or two. Just a thought, plugs don't cost much and then you could start looking.

aalbert
04-14-2003, 12:20 AM
BTW as a recap on this, it turns out that one of the jets in the top carb had backed out, and was restricting movement of the float.

-=Andy