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Yamaha 1989 200etxf carbed 2-stroke lugs under load

Baymaster

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Original owner. Well kept with few problems over the years. Faithfully fogged and treated with 2+4 for layup, and spray tuned in the Spring, every season. Nothing but Ring Free during fill-ups in the gas tank, and Yamalube in the oiler. Fuel/water separator since new. Other than some redish/orangish discoloration on the plugs, they look "normal". Plugs are new every Spring. It's been getting 10% ethanol gas since that crap came out. Also detecting(imagining?) a little knock.

Motor idles ok, but lugs during take-off, and when accelerating. Once up to speed, it purrs and hasn't lost any rpm's or speed. Runs at full throttle as good as it has since we got it.

Best guess?

Thanks a bunch, [email protected]
 
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Thanks for that reply. I had two guesses about (non-serious mechanical) stuff, and that was one of them. Other was "bad" fuel, which I thought it COULD be, because boat sat for longer periods over past few seasons....7 months this time, and it hasn't had the use it needs to run thru all 100 gallons lately.

If you can believe it, carbs have only needed rebuilding once in all those years, and that was just a few years ago. To keep 'em clean, I spray tune the heck out of them each Spring. Maybe that hasn't been enough?

The fuel/water seperator has kept much of any visible small stuff, showing up (less and less) since using ethanol, from reaching the filter under the cowling. Recognizing it doesn't take much to clog a carb, I still didn't figure enough of anything was getting thru to be a factor, so could be wrong about that.

Also hoping this thing isn't suffering long term effects of ethanol. I don't know, and hope not.

Again, thanks for your input. Much appreciated to hear what others think.
 
When you say lugging are you seeing/hearing a blubbering note with extra smoke and a gradual clearing as the load increases?
 
When you say lugging are you seeing/hearing a blubbering note with extra smoke and a gradual clearing as the load increases?
No to the note and smoke. Haven't noticed on the tach about when it clears, and can only say, without more attention, that it smoothes out when throttle reaches a certain rpm level. I noticed near the end of last season that engine wasn't up to its usual smooth operation at lower rpm's. Seems worse now...lasts more into higher rpm's...... but like I mentioned, still runs well at top speed, except for maybe a VERY slight perceptable knocking sound thruout its range.
 
That vintage was known to have problems with wrist pin pound out. I'm wondering how many hours on the fuel lift pumps. Could have some bad diaphragms leaking fuel into the crankcase.
 
That vintage was known to have problems with wrist pin pound out. I'm wondering how many hours on the fuel lift pumps. Could have some bad diaphragms leaking fuel into the crankcase.
Thanks for your continued input here.

Well, being a driveway mech only, I have very little knowledge of what a "wrist pin pound out" problem can be, or what could happen if not taken care of. I suppose a blown engine. Sounds like remedial maintenance would be an engine tear down for a 10 dollar part? Otherwise sounds like I could lose an engine while out on the water if not detected or taken care of now? Also, how can a mech know for sure if a wrist pin needs replacing?

Only way I have of keeping track of hours on this engine is guesswork. Based on our limited use during available time, and the kind of fishing we do, I'd say this engine has less than 1500-2000 hrs over its 22 year life span. I've changed the fuel pumps once during that span, so they have fewer hours than that.

To make stuff last longer, and also to save money in the long run, I believe you can't be too overly cautious about interim maintenance, which makes me appreciate all the help here! Any other lessons about known problems with this age/model engine are also welcome! Thanks all!
 
Wrist pin is piston pin and you are looking at 6 pistons and a bunch of other parts. These can run quite a long time with that going on though so if that is it I wouldn't get to cranked up just yet. It usually progresses very slowly. That will be your clue.
Back to the lugging, as was mentioned before I think I would be good to know that the carbs are not the problem.
 
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