7.4 mercruiser missing at full throttle

[vicdur93]

I have a 1997 baja with a 7.4 300hp mercruiserThe engine runs fine until I go too full throttle then the engine seems to start sputtering or missing, When I back it off it runs fine and still is turning 4800rpm. Is there a rev limiter on this engine and it is cutting off or is the choke comming on?<br /> I have a 23 pitch prop on this boat.<br />thanks for any help to fix this problem.

 

[vinney]

Re: 7.4 mercruiser missing at full throttle

Your hitting the rev limit. Does you prop have a rubber hub or have you been playing with different props. Your over revving the engine. If its a rubber hubbed prop remove the prop and smell the hub If it smells like burn't rubber the hub is spun. If you do have a spun hub you can have it repaired But all the new style props run a plastic square hub because of the higher horsepower engines outboard/IO's.

 

[vicdur93]

Re: 7.4 mercruiser missing at full throttle

When you say the rubber hub is spun, is that in the prop? It is not in the out drive?The person I got the boat from the prop was missing and he put a used 23 p on it That prop might be bad. I will return it for a different one then if the hub is in the prop. thanks

 

[vinney]

Re: 7.4 mercruiser missing at full throttle

The rubber hub is in the prop. If someone gave you the prop. Its probably has a spun hub. We don't use rubber hub props anymore. We use the new style plastic square hub props. A spun hub can give you alot of headaches.