No propulsion at higher rmp

[Lukiebs]

Hi ,new here.
I have an 115 v4 johnson about an 78 model or so. I have not foward or reverse propulsion when i up the revs. I'm lucky to get to 5 knots. The engine just revs out but not drive. At lower rev it just moves the boat. Any ideas? Also I took out the lower case and there was a little bit of shaving on the magnet but the drive shaft look fine.
Thanks

 

[5150abf]

Re: No propulsion at higher rmp

Welcome to iboats.

The first thing I would do is rule out a spun hub, there is peice of rubber between the prop blade and the sleeve that goes on the shaft, occasionally the bond between the rubber and the sleeve will break and allow the prop hub to spin but not the prop.

Put a mark across the back of the prop and run the boat then check to see if the marks are still aligned.

 

[Vic.S]

Re: No propulsion at higher rmp

The first thing I would do is rule out a spun hub

I dont know about rule out. The most likely cause of the problem I would have thought.

Mark the end of the shaft and the prop. Give it a run and if the marks no longer line up there's the problem.

 

[Lukiebs]

Re: No propulsion at higher rmp

If it is a spun hub do i replace the whole prop or just the inner sleeve?

 

[5150abf]

Re: No propulsion at higher rmp

Either, replacing the sleeve requires a prop shop, not something you can do yourself but you can get a new or close to new prop on ebay for probably less than either of those options.

Check the to be sure yours is spun first, it could be something else too.

 

[HighTrim]

Re: No propulsion at higher rmp

If it is a spun hub do i replace the whole prop or just the inner sleeve?

That actually depends on what type of prop you are running. If it is a 2 piece prop ?? then you can simply replace the inner sleeve in seconds. If it is a standard 1 piece prop, then you will have to have it rebuilt by a shop as stated.

I have just personally bought a couple of the 2 piece props, so that if you ding the outer blades, you simply replace that section, if you spin your hub, you replace the inner sleeve. The inner sleeve can be replaced for under 50 bucks, the outer for under 100. EIther scenario is then much cheaper than having it rebuilt, or buying new, and you always have a near new prop. Sounds good in theory, we will see how they perform on the lake this summer.

 

[Vic.S]

Re: No propulsion at higher rmp

We dont know for sure what year it is, a model number would ID it!

The parts list for 1978 does show a separate hub #82 in THIS DIAGRAM part number 384977