1984 150hp no power at prop

[BJBUSYBOY]

When i'm on plane and throttle down slighty to where the boat is halfway out of plane I thottle back up to get back on plane and have no acceleration. The RPM's shoot up as it should but no power?? I have to completely come out of plane and restart and works fine then. It's almost like it's not in gear when this happens but i don't take it out of gear and when it fully comes out of plane it IS still in gear and moving forward. Does this seem like a symptom of a spun prop? BTY, gear oil changed every season and no water intrusion ever in the gear case. Shifts great FWD AND REV. Please help

 

[Barnacle_Bill]

Re: 1984 150hp no power at prop

It does sound like you are slipping on the hub. You can check it by putting 2 marks on the prop opposite each other. One on the inner hub and one on the outer. Try it again then check to see if the 2 marks are still lined up.

 

[tashasdaddy]

Re: 1984 150hp no power at prop

do you have trim and tilt? do you trim out after you get on plane? do you trim down as you come off plane? you could be just sucking air, it not adjusting the trim. a spun prop would not get you back on plane after coming off.

 

[BJBUSYBOY]

Re: 1984 150hp no power at prop

I do have trim and use it. And I do not trim down while throttling down. The hole shot is like a cat trying to get out of water once i fixed the slugged timer base.... so your right, it wouldn't be a spun prop. So while pulling a tube it would probably be wise to leave trim down as there is a lot of slowing down and speeding up!! I'll burn a lot more gas but at least i won't have to come all the way off plane to start over!!! This is the best forum ever!!! Thanks TD

 

[emdsapmgr]

Re: 1984 150hp no power at prop

Your ventilation problem may be as a result of having the engine mounted higher than normal on the transom. This is a racer's trick which provides better top speed, economy by reducing the drag from the lower unit underwater. High tech stainless props minimize this problem, but you will need to trim in when at low speeds to keep the prop hooked up.

 

[CharlieB]

Re: 1984 150hp no power at prop

When trimmed down such that the cav plate is paralell with the boat bottom, how far is the plate from aligned with the bottom?

Assuming that the motor is mounted higher than even.

Measure and tell us.

 

[BJBUSYBOY]

Re: 1984 150hp no power at prop

I'll get that measurement and reply back!!