Motor Revs High in vegitation

bustermin

bustermin

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I have a 1984 75hp Chrysler model 756H4L. i was out on the boat this weekend and when i would hit a patch of grass or vegitation even at wot, the engine would rev and forward motion would slow. it act almost like there is some sort of clutch for the prop and it slips when there is resistance, it that whats going on? or is there a problem? when im not in the vegitation it runs great no problems (although reverse seems a little slow, but i think that may just be a cable adjustment issue)
 
HAV2FISH

HAV2FISH

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Re: Motor Revs High in vegitation

It sounds like you might have spun your prop. Draw a line on the back of the prop and over on to the lower unit. Now put the boat in the water and run it for a few. Then check the lines. If they are not lined up then your prop is spun. Remove it and take it to be repaired. Just a spun prop repair is only about $50.00 or so.
 
bustermin

bustermin

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Re: Motor Revs High in vegitation

if i understand right. you think it is the prop that is the problem, i thought when the motor spun a prop it would slip all the time, mine seems to work fine unless i get into some type of debris. i have never experianenced a spun prop so im not sure if this is it or not (maybe this is my first) i did mark the prop and put in water and it did not seem to move, but i was not in any vegitation (couldnt find any). any other ideas, im going to go back later and try to get into the vegitation at the lake i was at when it first happened.
 
HAV2FISH

HAV2FISH

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Re: Motor Revs High in vegitation

I still think it's a spun prop. With out being in the vegetation your prop might still be tight enough not to slip. The only other thing i can think of would be a bad gear or lower unit. I would thin if that was the case it would be more obvious.
 
Frank Acampora

Frank Acampora

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Re: Motor Revs High in vegitation

Dont go into the weeds! They wrap around the prop and lower unit, fouling the prop and reducing thrust. The prop then has little resistance in the water and the engine revs up without going anywhere. Quite a common problem.

Once out of the weeds, the plants break off or spin off and the engine returns to normal. In severe cases, you need to tilt the engine and manually clear the prop.
 
bustermin

bustermin

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Re: Motor Revs High in vegitation

i put a mark on the prop, and went thru vegitation. the mark did not move. also now it revs like its slipping or somthing when i make a right turn at anything over half throttle ( it does not do it when i turn left).
 
J

jbwillis76

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Feb 20, 2009
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Re: Motor Revs High in vegitation

Right turn sounds like cavitation. Trim down and see if it still does it.

James
 
bustermin

bustermin

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Re: Motor Revs High in vegitation

i cant trim down, it has manual trim/tilt. also it is set to the lowest position.
 
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