28HP Prop help

[Redline36]

Hello,
I am new to iboats and I thought this may be the best place for some help.
I have a 16' fiberglass Cheetah Bass boat with a 1988 Johnson 28SPL 9x9 prop which was originally on a Pontoon boat. The trouble I am having is with just myself in the boat I can just get up on plane and it sounds like the engine is sceaming. If I add another person (150#) the boat just does not want to get up on plane and does no have much speed even though the engine sounds like it is screaming. Sorry but the tach does not work so I do not know actual RPM. Should I change the prop to a different pitch or am I just to under powerwed with that 28HP motor?
Any suggestions would be greatly appreciated.

MikeG

 

[steelespike]

Re: 28HP Prop help

The 28 should plane easily with two but not with much to spare.
The 9 isn't enough prop and changing a prop without a tach is a crap shoot both for performance and motor health.If I had to guess perhaps a 12.That should lower rpm by about 600. Yet push pretty good.If you suspect the least bit it may be over reving throttle back a little.It is better to be under propped a little at least you can run it if you stay below the revs. If you endup over propped you would have to operate at greatly reduced speed
to prevent lugging.Get the tach fixed it may just be loose or corroded connections.

 

[Rancherlee]

Re: 28HP Prop help

Hello,
I am new to iboats and I thought this may be the best place for some help.
I have a 16' fiberglass Cheetah Bass boat with a 1988 Johnson 28SPL 9x9 prop which was originally on a Pontoon boat. The trouble I am having is with just myself in the boat I can just get up on plane and it sounds like the engine is sceaming. If I add another person (150#) the boat just does not want to get up on plane and does no have much speed even though the engine sounds like it is screaming. Sorry but the tach does not work so I do not know actual RPM. Should I change the prop to a different pitch or am I just to under powerwed with that 28HP motor?
Any suggestions would be greatly appreciated.

MikeG

If ya happen to get rid of the 9x9 let me know, I need one for my pontoon I just bought (9x12 is the prop shipped with it from the factory). I'd swap ya the 9x12 but it has a big chunk missing out of one blade.

 

[Redline36]

Re: 28HP Prop help

Steelespike thanks for you input, I found a 12 pitch for a decent price so I will give it a try after I get my tach working. I stated working on the tach issue over the week end and I ended up tearing out the rats nest of wiring under the dash and redoing from scratch. I hope to have it complete by the time the prop arrives.

Rancherlee the 9x9 looks to be new so i will probably save it for a spare. If I change my mind I will let you know.