Fellas - I put the post below up about a month ago and am still having the same problem. Since this post I have (carb job, new carb gaskits, run sea foam, changed fuel line and prime bulb, changed fuel line connections, checked fuel filter,new gas, changed plugs). Still doing the same thing, gets up and goes then slows down after 1-2 minutes. Compression is 100,100,100. Please let me know if you have any other advice. Thanks!
I have a 97 40hp yamaha percision blend. Before I put it in the water yesterday mechanic told me to run it with one tank of a low gas/oil mix then from then on got to straight gas. Motor did great and would jump out of the hole and get up to 30mph quick…then after 1-2 minutes is would slowly lose speed and creap all the way back down. It actually stopped doing this after a few tries and I creaped back to the ramp at 5mph(it held that speed consistantly). I even went and got new gas thinking it may have been bad gas or the oil gas mix. One of the spark plugs also looked a little fouled.
you might have originally mixed too much oil with your gas? or maybe replace your fuel filter
WHY DID THE mechanic tell you to do that?
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the motor had sat for a while and he said the bearing needed a little extra lube at first.
okay, not sure why it would need extra oil at first, and then not need it later, just because it sat for a while, unless you had a rebuild done or something like that, but, nothing really bad is gonna happen from a little extra oil.
sounds like from sitting, you have possibly varnished up a carb, and the fresh gas after a little running dislodged some debris, and you have a restriction in the carbs. gonna probably require rebuilding the carbs
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Thanks for the help Chris. Not sure if it would make a difference, but he did rebuild the carbs about a week ago. I did not have new carbs put in, but he soaked the old ones and cleaned them up. Also, when I got home and looked at the motor the fuel filter was laying in the bottom of the motor, but everything was still attached(don’t know if that would affect anything).
hah yea that might be the problem. fix the fuel filter and you should be strait. if not then…well… i cant help you any further sorry
sounds like your mechanic may be the root of your problem…
still sounds like a carb issue
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