Proper prop size?

[maverick974]

I have a 1984 Bayliner Trophy bass boat. 16 footer with the original 85 hp Force engine. I've pulled the prop and I can't find any numbers anywhere. The prop is bent a bit and I want to buy a new prop and use the old one for a spare.
Does anyone know the original prop size and/or can you recomend a good prop for this boat?
I'm usually fishing alone or with my girlfriend with a fairly light load. 1/2 tank of fuel, a few tackle boxes and a few rods.

 

[Lyle29464]

Re: Proper prop size?

A prop shop can fix it for a spare and sell you a new one the same size if your happy with that one.

 

[fucawi]

Re: Proper prop size?

your problem is that the right prop runs in the rev range for the motor at WOT( Shown on the spec plate ) on the boat your outboard is fitted to ..you may find a number between the blades under the paint or on the hub which you might match at mitchigan props..on the web. What your really need is to borrow a known prop ..run it and measure the rpm and then adjust what you want knowing that a change of 2 in in pitch will change the revs 400 rpm...

 

[jerryjerry05]

Re: Proper prop size?

Someplace on the prop is a #.It could be between the blades or on the end.
That boat and motor came witha 17 or 19P prop.
Check the local boat dealer,most work with a prop repair shop.Get it rebuilt.They might even have another for a spare.J

 

[maverick974]

Re: Proper prop size?

I finally found some numbers. They were under the paint. It appears it's been repainted several times so the numbers were obscure.
It reads 524-19 so I'm assuming that means a 19 inch pitch. I took a tape measure to it and it looks like it's a 12.5 inch diameter give or take a quarter inch.
The problem with my boat is that it has no tach and the prop has at least one bent fluke and the edges have been filed so I really don't know the exact diameter.
Just by the sound of the engine and the "feel" of the rpm's, I'd say with the current prop, the RPM's are a touch high but obviously without a tach, there is no way to tell for sure.
2 years ago, I bought a 4 blade comp prop for it and I was very happy with the performance. It was a 13X19. I lost some on the whole shot but gained 10 mph top end. I was actually very please with the plastic prop until my brother borrowed my boat and promptly took out all 4 flukes on some rocks. I thought about buying another one but if it broke all 4 flukes that easily, I figured I'd go with aluminum since I'm in shallow water bass fishing most of the time. Unfortunately, single exhaust Force props are getting hard to find and very expensive.

 

[steelespike]

Re: Proper prop size?

Boy the old prop must have been pretty bad or perhaps a 17"
An induction tach like a Tinytach will work or an optical tach.
Or perhaps borrow a shop tach.A gps for speed.
The right prop for correct rpm is important for best performance and motor health.

 

[Jiggz]

Re: Proper prop size?

If you were happy with a 13-19 4-blade plastic prop I don't see any reason why you cannot get an Aluminum 3-blade for a replacement. Iboats has them and it seems the standard prop is a 13"-19P 3-blades.

 

[Silvertip]

Re: Proper prop size?

Actual diameter varies from 13-1/4 to 13-1/2 depending on manufacturer. It is part of the prop design and is of little concern provided the prop is specified for your particular engine. Pitch has much more effect on performance than diameter.