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Props
Posted: Mon Oct 31, 2016 4:19 pm
by mtwolf
I would like to know the correct size props for an F-31 1973 Trojan? Two 318 Chrysler 225 H.P. engines.
Re: Props
Posted: Mon Oct 31, 2016 5:50 pm
by prowlersfish
I don't have a listing on the F31 , But Assuming you have a 1 to 1 gear on you 318s this sold be close F30 can with 14x11 and the F32 can with 14x10 both small cup .
Re: Props
Posted: Tue Nov 01, 2016 11:46 am
by mtwolf
prowlersfish wrote:I don't have a listing on the F31 , But Assuming you have a 1 to 1 gear on you 318s this sold be close F30 can with 14x11 and the F32 can with 14x10 both small cup .
Thank You.
I could only get about 2800 at WOT. Have to take a wire brush, on a drill motor, to a prop and see what size. Also I want to hook up a Tach Dwell and see what the actual R.P.M. as compared to the boat tachs.
Re: Props
Posted: Wed Nov 02, 2016 11:29 am
by larryeddington
My 1:1 F28 with the 318 225 has 14/11 s and it my rpms only get to 3300 IMO it is too much prop, I have a set made into 14/9s but have not had a chance to try them on. I am not getting the speed or RPMs I should with the 14/11s
Re: Props
Posted: Sun Nov 06, 2016 11:38 am
by Lou
I have an F31 with twin Ford 351, 255 hp with 1:1.52 and swing 16x16 props. I cruise around 26-28 mph at 3200 rpm, topping out in low 30's. From any research I come up with since the F31 is a hard to find... The F32 is not too far off. With the 318 I would suspect 14x10 props.
Re: Props
Posted: Sun Nov 06, 2016 3:47 pm
by prowlersfish
Knowing the gear ratio would be a big help .
Lou did you see my F36 at dandy ? Haul out in May and engine swap in June .
Re: Props
Posted: Sun Nov 06, 2016 6:11 pm
by Lou
prowlersfish wrote:Knowing the gear ratio would be a big help .
Lou did you see my F36 at dandy ? Haul out in May and engine swap in June .
I did see the post you made, I had moved my boat to the Portsmouth area for a beautification process as it is closer to home.
Re: Props
Posted: Sat Nov 19, 2016 9:59 am
by mtwolf
Finally got to the Marina yesterday, nice warm day. Removed about thirty seven layers of bottom paint, with a wire brush on a drill motor, to read the numbers on the prop. Turns out they are 14X12. I wonder if this was done for better fuel economy will sacrificing a higher top speed. I normally run about 2500 rpm. Up on plane, runs along just fine. I want to take the pair to Miller Island Prop, have these redone, and get an expert opinion from someone who knows props?
Re: Props
Posted: Sat Nov 19, 2016 10:34 am
by prowlersfish
I would knock them down to 14x10 . While you will be cruising at a higher rpm the engine will not be straining as much and will jump on plane easier . Your engines will thank you .
Consider ablative paint wears off so there is less build up .