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What Prop do i need?
Posted: Fri Jul 03, 2015 1:00 pm
by trojanwars
I have a 1979 Trojan 30 express with twin 225 and two questions
The hull has been repainted and rebuilt motors but it will only get up to around 3300 RPM at W/O throttle. Motors should run up to 4000 RPM. I have looked everywhere trying to find what props should be used, does anyone know what sizes should be used? and what is the displacement?
Thank You, Jerry
Re: What Prop do i need?
Posted: Fri Jul 03, 2015 8:37 pm
by Big D
Hi Jerry, welcome aboard. I'm sure another 30 express member will chime in with their 2 cents. You could also try Beacon, the sponsors of this site. They will likely have all the specs you need. Again, welcome aboard and hope we can be of help with all your questions.
Re: What Prop do i need?
Posted: Sat Jul 04, 2015 7:08 am
by Lou
Here's what happened to me when I could not reach WOT. My brother put new idle screws on my carbs, they were 1 1/2" long. They prevented me from reaching WOT. I cannot find the original screws he took out, so I just got shorter ones so I can reach my WOT. I went through everything trying to figure out what the issue was.
Also ale sure all fuel lines are free of trash. That became my next issue.
Re: What Prop do i need?
Posted: Sat Jul 04, 2015 8:13 am
by prowlersfish
My 77 f30 had 14x10 props
Re: What Prop do i need?
Posted: Sun Jul 05, 2015 12:49 pm
by trojanwars
Hello everyone!
Thank you for any info you can supply. I really want to get some better props but I can not find what the weight is, I have tried the prop calculators but the weight is a factor and I was told it is 11,500 lbs and also 8,100 lbs!
Re: What Prop do i need?
Posted: Sun Jul 05, 2015 5:47 pm
by prowlersfish
8100 was Trojans listed weight dry ( no fuel/water or gear ) 14x10 was what mine had new
Re: What Prop do i need?
Posted: Tue Jul 07, 2015 12:15 pm
by trojanwars
Thank you all for the info! I do think the props were replaced, I have a better idea of what props I need
Now the prop calc will work better! The props are only 10".
Re: What Prop do i need?
Posted: Tue Jul 07, 2015 1:05 pm
by prowlersfish
10" dia ???
Re: What Prop do i need?
Posted: Tue Jul 07, 2015 3:31 pm
by trojanwars
YES!! I think someone must have broke one and replaced them with wrong sizes, I have to go full throttle just to get her up too about 15 knots. 20 knots is the max at around 3300 RPM, a real dog!! I also think the stock carbs are way over sized, 800 cfm carters are crazy big for a 318, at 4,000 RPM a 318 will only pull 368 cfm so I am also looking for two 450 cfm marine carbs that will bolt on easily.
Re: What Prop do i need?
Posted: Sat Jul 11, 2015 12:17 pm
by trojanwars
Did your 77 have twin 225s and what is the shaft size?
Thank you
Re: What Prop do i need?
Posted: Sat Jul 11, 2015 5:23 pm
by prowlersfish
233 hp mercs 1" shafts The F30 came with 14x10 or 14x11 both listed as cupped . FWIW I found some Trojan info that listed the F30 as 8100 w/single engine and 9000 with twins . Most the info I had seen list them as 8100 with no reference to engines
Re: What Prop do i need?
Posted: Sun Jul 12, 2015 12:56 pm
by trojanwars
WOW Thank you PF! I really appreciate all your info