1979 SST Prop?

[THutch]

I'm new to the forum and you guys are great, and entertaining. Last year I bought a '79 SST w/ an '88 Johnson V4 110hp. Obviously its an old boat but in pretty good condition. When I have some cash, I'd like to rehab it, but until then, I'm just trying to get it to run well. The motor runs fine and I don't have the boat loaded down. Typically on board I have trolling motor, 2 batteries, 1 fishing seat and light tackle. What is a good prop for this set up? Currently I have a 22 Raker and it rides OK. It runs out about 55mph gps w/ slight chop on the water but the RPM gauge reads 6200 which seems way to high. RPM guage seems to read right and the motor definately sounds like its wound all the way up so I have every reason to believe it is reading true. The boat will run on plane at 4000 RPM or more. I put a hydrofoil on the motor and that seems to help holeshot but I feel like its just masking the real issue, wrong prop. The prop shaft is about 3 inches below pad and I do not have nose cone water pickup on the lower unit. Any suggestions? I'm not really interested in spending the money on a new lower unit, but if that is the answer, I'll listen. Thanks in advance for any ideas.

 

[THutch]

Bump. Rattle. Any ideas.

 

[SLOmofo]

We, being OMCease owners are at a information disadvantage. If you havent already click on the "Quick Links" tab at the top of the page, then click "Owners Stuff" then "Older Allisons" you can get ideas there.
I would be sure of the tach reading and then If you don't have one, get a water pressure guage and a GPS.
With this base info: top speed/rpm, hole shot, water pressure you can start changing things ONE at a time and see what is or isn't an improvement over your Base Line.
I believe your engine is a cross flow, they can be made to run but as with every thing where there is a + there is also a -.

As for props try every thing you can get your hands on. I use mostly modified choppers(merc) and modified SRX (OMC). There again I have a XB2003/200+ JohnRude.

 

[THutch]

Thanks for the info and suggestions. I have a gps but likely need to head out with about 1/2 tank of fuel and run it hard. I'll take GPS readings at different RPM to see if that tells me anything. I'm no machanic, but I suppose it could be geared in a manner that would make the RPM of the motor misleading in judging prop rpm. I suppose I need to find a way to try a 24 or 25 pitch to see if that is way to much. I suspected I was fighting an uphill battle.