scurtis

Hey guys,

A few months ago I requested some insight on a problem w/my 25hp Merc. She starts no problem and idles great. But when I get out she only runs half power. Every now and again it will just "kick" in and go fullpower. It was suggested that I replace the ignition coils, which I did for short money (one of the magnets was cracked). I thought that would do it but I just had her out last week and still running funny. I let it warm up for a bit then ran and just the same. You can goose the throttle but only get half power. Again, every now and again it kicks in for a second but then drops back down. It seems to me this is some sort of electrical problem because as I said it does go sometimes. Any other suggestions?

Steve

Scup

It does sound like an electrical problem to me, but with the crappy fuel they are selling us for $5 per gallon, I would still try to eliminate something that is easy to correct first. Todays fuel will start to break down after just a few weeks. Siphon your old fuel into a clean container as it still might be fine, and try a fresh batch of fuel mix. Pour a small amount of the old stuff into a clear container and examine it visually and by smell. It is hard to describe, but old fuel takes on a characteristic smell. Check your fuel filters if you have not done so already. If you have a clear bowl type of fuel filter, see if it remains full when your engine starts to act up. While not recommended, more than once I made it home by pumping the rubber bulb to keep my RPM up when things got partially clogged up. If any of the above helps, then it just might be fuel problem. If not, then as you claim, it is probably electrical. Intermittent electrical problems can be a bitch to find. Even pros can end up scratching their heads on this type of problem. Since they charge $$$$ by the hour, should you end up having to take to a shop, pick the best one you know of. Even a honest shop can end up spending quite a bit of time trying to find an electrical intermittent problem so it will end up costing you less by having a pro go right to the heart of the problem.

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"Success seems to be largely a matter of hanging on after others have let go" by William Feather

scurtis

Thanks for the reply. This problem started last year and as you suggested I thought it may be fuel. I drained and replaced fuel, changed the fuel filter and lines, and installed new plugs. I'm at a loss! Thanks for the effort though. I have just been trying to avoid a mechanic as I know the cost to trouble shoot is probably more than the engine is worth. It's an 86 with a lot of hours but she ran like a top until this started. A buddy had metioned a stator (I think). I had a few other suggestions but forget what they where when I found the broken magnet on the ignition coil and assumed thats what it was. I guess I have to keep on trying. Thanks again.

Steve

Scup

Steve, I now think you are right about it being electrical. You are also right about bringing it in to a shop. Even a good shop could spend a lot of time of troubleshooting an intermittent problem and it does not take too many hours for the bill to add up to something more than the motor. What is disturbing is it does run well at times, meaning the problem is likely something miner like a high voltage wire arcing over sometimes at high speeds. My last suggestion is try running it at night with the hood off and look closely and listen for characteristic sound of a snapping arc. Last fall I took my 25hp into a reputable shop for just winterizing (I am lazy plus being commercial it is a write off for me) and ended up getting hit for a several hundred dollar tab. Unless I really have to, taking my engine in for work is now a last resort. Wish you well, and if you find the problem clue us in on what it was!

__________________
"Success seems to be largely a matter of hanging on after others have let go" by William Feather

scurtis

Scup,

I never thought to run it at night and look for a spark. Thanks for the idea. If i find out I will let you know. Thanks again.

Steve

On The Edge

I just had a simular issue with my old 40 mariner on my bass boat. Carb was gummed up big time. Draining and changing the fuel and filter will not fix it. I had to remove the carb and completely dissasemble and clean it with CRC Carb cleaner. Runs like new now..

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Catch um up

1999 proline 2202 wa
1999 200 merc

scurtis

Alrighty then. Unfortunately, I havent the ability (knowledge) to do that. I have to pick up an owners manual for this engine then maybe give it a try. Right now I just know if I take it apart I'll have extra pieces when I try to put it back together. Thanks for the insight though.

SC

bjanisieski

I work on snowmobile, personal watercraft, atv's, but not boat motors. From my experience with 2 strokes though it doesn't sound like the stator because usually an engine will only run for a couple minutes when the stator is bad, it's kind of like when your altenator in your car goes bad and the car dies. The stator works just like an altenator. I would check all your ground wires also, also see if you have strong spark coming from the spark plugs. Also like OTE said I would definitely clean the carb, we have noticed with this high quality (LOL) fuel we have now a days that carbs are getting gummed up like crazy. I tell everyone with a small engine to stabil there fuel even if they use it right away. I know a guy who owns a marina and 65% of there service work is now fuel related! Just my insight....btw my father a 1988 20 Merc that did the same thing ever since it was new, brought it back and got yami 9.9 4 stroke.