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Johnson MQ-14e 9.5hp Slipping

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kevinb619

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This engine is costing me a pretty penny for the junk it is. It runs great but over 5mph it slips out of gear, I spent $300 replacing the clutch dog and forward gear and its still doing the same thing. I shouldn't even say it's "slipping" because when I back down the rpms the boat starts moving again. If it slipped out of gear it wouldn't move until I put it back in gear. So I thought it might be the prop hub but it doesn't look like this particular model has one, it spins with a drive pin. Could the boat itself be a long shaft boat and how can you tell besides looking at the plate? (took that off so I could use old CF numbers on this new boat hull)

Other info that might be helpful, I recently put on a hydrofoil. I had the problem before but no where near as bad. Could this play into it at all?
 
If the sensation feels like you're constantly and intermittently hitting a submerged object.... then yes, the engine is jumping out of and back into gear.

However, if the sensation is such that suddenly the engine increases in rpms and the boat slows down... and it stays that way until you lower the throttle setting, then you either have a slipping bronze hub within that aluminum propeller...OR... you have a shaft shaft engine installed on a long shaft transom.

Now.... which sensation are you encountering?
 
joereeves said:
If the sensation feels like you're constantly and intermittently hitting a submerged object.... then yes, the engine is jumping out of and back into gear.

However, if the sensation is such that suddenly the engine increases in rpms and the boat slows down... and it stays that way until you lower the throttle setting, then you either have a slipping bronze hub within that aluminum propeller...OR... you have a shaft shaft engine installed on a long shaft transom.

Now.... which sensation are you encountering?
Click to expand...

The second one for sure. The dinghy I have says it requires a 15in shaft which is what the johnson 9.5 is. I'm going to take the prop in but from what I've been told it didn't have a hub.
 
It does have a rubber drive hub !-------------I used to have one cut open with a hacksaw to show those people who simply do not believe simple facts.
 
Last edited:
Kevin..... My reply post #9 (which I'm sure you caught) states "OR... you have a shaft shaft engine installed on a long shaft transom." (My Apologies)........

It should have read "OR... you have a short shaft engine installed on a long shaft transom."

The height of your transom indicates whether you need a short or long shaft engine. Measure the height at the keel..... in the neighborhood of 15" = short shaft...... 20" = long shaft.
 
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