15 hp evinrude wont stay at full speed

muskiemike12 · Post by **muskiemike12** » 08 May 2013, 12:54

Do you have answers to my ?'s

muskiemike12 · Post by **muskiemike12** » 08 May 2013, 12:56

Try changing the thermostat. Was the motor ever used in saltwater?

BoatingCop · Post by **BoatingCop** » 08 May 2013, 13:04

Does your prop still have the converging ring on it? If not factory, is it flared? Does it sound as if its cavitation? To see if its getting hot, try touching the head. You should be able to leave your hand on it for a few seconds. If you can't touch it at all then it's overheating.

chrisc54 · Post by **chrisc54** » 08 May 2013, 21:24

okay, so yeah thats not my motor or boat just an example of my motor but an older version. Mine is a 1992, the rpms drop with the speed when it slows. The prop does have a small little ding in one of the prop blades but it never affected it before. When i started my motor for the first time this year it would run and then die in forward...so i brought it home ran seafoam through it and tinkered with the carb settings and it was good. The year before i never had a problem so i assume it was just running out the cobwebs, it only sat for 4 or 5 months, the motor is mainly used in saltwater and then flushed out

chrisc54 · Post by **chrisc54** » 09 May 2013, 19:28

so i took the lift off of my transom, it is now 15" high and i have a short shaft, (which is proper)?...i had it lifted roughly 4.5 5" higher so much to high for a short shaft, although when idling or going slow it was okay but i think that when i went full speed its possible that even the water pump intake wasnt getting in quiete enough water,. Testing it tomorrow hopefully

muskiemike12 · Post by **muskiemike12** » 10 May 2013, 10:06

Chris,
Here is a tip from now on. Don't post pics of other boats to try and explain an issue. Everyone on here thought that was your boat and saw no problem with the setup. In order for any of us to help you we need the correct information. Putting your motor back on the 15" transom is the right move and will solve all the issues you were having. Remember the cavitation plate should be even or slightly (1/2") above the bottom of the boat.

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