1979 70HP Johnson

[glowpowered]

Finally took the boat out after transom replacement http://forums.iboats.com/showthread.php?t=413481 and 10 years of sitting. Ran good, except twords the end of our 45 min run time the motor started to act like the prop had no bite. From reading around i understand this could be one of two things. Spun prop hub or cavitation? My question is can the prop on this motor "spin"? The motor had some sea weed on the drive unit when we pulled it out, could this have caused cavitation? Thanks, Luke

 

[SeaScallop]

Re: 1979 70HP Johnson

The motor had some sea weed on the drive unit when we pulled it out, could this have caused cavitation? Thanks, Luke

Yes, grass or seaweed can cause cavitation. How much was on there?
Out in the northwestern gulf we have manatee grass that does a good job of blocking the water inlets too...

 

[glowpowered]

Re: 1979 70HP Johnson

Yes, grass or seaweed can cause cavitation. How much was on there?
Out in the northwestern gulf we have manatee grass that does a good job of blocking the water inlets too...

It wasn't a whole lot. Also, i came to almost a stop and tried to go and it had trouble getting traction.