Engine slows at 4500 rpms

Sea Mitch

Petty Officer 2nd Class
Joined
Jan 9, 2002
Messages
135
I bought a used Yamaha '93 250TXRR serial # 61AUL-702987. I got gas and went for a ride. I was cruising at about 4500 rpms for about 45 minutes to an hour when all of a sudden the engine slowed down. I lowered the throttle as gut reaction and it stalled. I turned the key to start it again and it started, although it started kind of like the batteries were dying (they're brand new), a slow crank as opposed to the usual fast crank. It idled fine. I'm not sure if the engine sounded any different I haven't had the boat too long, this is my first boat and I've only been out 5 times so far. I don't think it sounded funny. Since it idled fine, I brought it up to 4500 rpms again. It got there for a couple of seconds before it died down again. When I put it in neutral it stalled. When I tried to start it this time, I got the click of an engine with a dead battery or bad starter motor. I waited about a minute to a minute and a half and tried again. It turned over slowly and finally caught. I was able to motor in at 2000 rpms without problem. The next day I added oil thinking this was the problem. It started up just like it was new. I motored through the channel at 2000 rpms (no wake) without a problem. I thought it was fixed. When I got to where I could open 'er up she did the same thing as the other day although when I brought it down, it didn't stall. I turned around and came in.<br /><br />I am pretty good with car engines but have no idea how to work on a '93 Yamaha 250 2-stroke on the water! I did a forum search as best I could using words like "rpm" "slows" and found most of the solutions seemed to involve fuel starvation. My marina doesn't have much time and I'm afraid I'll miss the season! Any suggestions are greatly appreciated. I don't think I'm capable of rebuilding the carbs but replacing plugs, wires, and lines I'll give a try! Thanks.
 

Sea Mitch

Petty Officer 2nd Class
Joined
Jan 9, 2002
Messages
135
Re: Engine slows at 4500 rpms

Oh well! I've had the boat for two months, went out five times and blew the engine. Welcome to boating I guess. Heard no noises, saw no lights, although the technician says they worked.
 
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