grouperjim
Well-known member
Boat is a 2320 with a 2006 Yami f250 and merc rev 4.
I was coming home from fishing yesterday and had been running 35 mph (4500 rpm) for about 3 hours. I got into some confused 2-3 foot chop a couple of miles out from the pass. I slowed down to 4000 rpms (29 mph). All was well for a few minutes, then the engine rpms would increase quickly but gradually about 500 rpms to about 4500 with no increase in speed, then back to 4000. I slowed down to troubleshoot. Shut the engine down, check the prop to see if I hit anything-- no visible strikes. Started up again and was barely able to keep it on plane--alot of erratic rpm increases/decreases. I thought maybe I was ventilating the prop with the 24w tabs but adjusting the tabs made no difference.
Finally got into and through the pass and into flat water. Idle speed for about 15-20 minutes. At the "resume normal speed" I hit the gas and everything seemed perfectly normal for the 10 minute ride to the ramp.
Today I cleaned the boat and pulled the prop. The prop nut was nice and tight. I knocked out the black plastic hub insert to inspect. It appears to be normal. I don't know what to think now. I thought for sure it was just a spun prop.
Is there something other than the prop that would cause these symptoms? Something in the engine or lower unit maybe?
Thanks in advance.
jim
I was coming home from fishing yesterday and had been running 35 mph (4500 rpm) for about 3 hours. I got into some confused 2-3 foot chop a couple of miles out from the pass. I slowed down to 4000 rpms (29 mph). All was well for a few minutes, then the engine rpms would increase quickly but gradually about 500 rpms to about 4500 with no increase in speed, then back to 4000. I slowed down to troubleshoot. Shut the engine down, check the prop to see if I hit anything-- no visible strikes. Started up again and was barely able to keep it on plane--alot of erratic rpm increases/decreases. I thought maybe I was ventilating the prop with the 24w tabs but adjusting the tabs made no difference.
Finally got into and through the pass and into flat water. Idle speed for about 15-20 minutes. At the "resume normal speed" I hit the gas and everything seemed perfectly normal for the 10 minute ride to the ramp.
Today I cleaned the boat and pulled the prop. The prop nut was nice and tight. I knocked out the black plastic hub insert to inspect. It appears to be normal. I don't know what to think now. I thought for sure it was just a spun prop.
Is there something other than the prop that would cause these symptoms? Something in the engine or lower unit maybe?
Thanks in advance.
jim
