Engine Over Revs.

[Jiggy]

Hi Guys,

Perfect weather, on holidays, on the water at the trag grounds off Coogee with what looks like kings on the sounder and the motor starts to play up. It had been running fine but when I went to move once I hit around 3000 revs the engine would start to over rev, it would jump up to 4500 or more then drop down and back up. Also I could feel that the prop wasn't biting, waterboiling at the back but not much forward movement.

None of the engine warning lights came on so it wasn't overheating etc. It was fine at 2500 revs and I crawled back to the ramp at 7 knots, but anytime I tried 3000 revs or higher the same problem. Checked the motor out in case of bent props, fishing line or anything else wrapped around it and it was fine. Engine in a Johnson 115 and it had a major service in January.

Any suggestions on what the problem could be?

Cheers

Jiggy

[a boat]

Hi Jiggy, I would bet you have a slipping bush in your prop. Remove the prop and inspect the rubber bush inside and I think you will find it melted.

No big deal, there are companies that can rebush the prop if not slipping too bad or about $250 gets you a new alloy prop or might pay to upgrade to a SST to get better performance.

Cheers,

Huey.

[Jiggy]

Hi Huey,

Terrific thanks for the advice.

Cheers

Rob

[1975]

same thing happened to me, melted bushe on the propeller, just got a new one