Trophy Prop Size

[utah1]

I have a 1992 20' w/a Bayliner Trophy. Motor is a 1992 Force 150. Currenly the prop on the boat is an aluminum 13.25x17

With just myself and 40gal of fuel, it will get up on plain and do about 30mph wot at around 5000 rpm

With 3 people and same fuel, it will only do about 15mph and will not plain out unless I have passengers go to the bow.

Could this be a prop issue or just a tired motor? The prop does have one small nick out of it and I have a new spare I will put on if I can find a hub.

Should I be considering a different diameter or pitch?

Thanks

 

[steelespike]

Re: Trophy Prop Size

No I don't think its a prop issue.More likely a motor issue.Assuming the boat is sound and gets up on the water as it should It should be running around 40 with little drop off for 2 more people.I don't know the gear ratio on thre 150 but would guess at least a 19 or 21" prop would be normal for most boating.A 17 for heavy loads with skiing.Motor would likely oiver rev with a light load.Be sure it is running on all cylinders,that the throttle plates are opening all the way.Bottom is clean and smooth.You might tickle the choke a little at speed and note the response.A compression check wouldn't hurt.

 

[thompy]

Re: Trophy Prop Size

i think you should be running closer to the 5500 rpm max with your prop selection, how is spark and compression on the motor

 

[Capt'n Chris]

Re: Trophy Prop Size

It could be a boat full of water. Oftentimes power issues are not power issues at all. Do you happen to have a transducer screwed to the transom?

 

[utah1]

Re: Trophy Prop Size

I have not checked the compression but will get at gauge this week and try it. Seems to be lots of spark and motor runs strong and sounds good but out in it today and realized that I am barely getting to 4700 rmp at wot. bilge compartment on boat is dry and it is a self bailing interior but you never know, i will pull it out of the water this week as well and check drainage on a steep grade.

Planning on repowering next spring as I just bought this boat this year, but really would like to get top performance for the rest of the summer, plus it will help when I go to sell it.

Thanks for all the suggestions,

UtAh

 

[thompy]

Re: Trophy Prop Size

what elevation you running it at seeing your in Utah?

 

[utah1]

Re: Trophy Prop Size

Actually I am in Ontario, Canada. Utah is just a nickname