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F32 won't plane, 2600 RPM max

Posted: Fri Sep 23, 2011 7:42 am
by RipTide
I have a 73 F32 with newer 350's approx 320 hours. I bought the boat recently. Previous owner said props are original. Engines check out great, compression perfect, bottom clean. Starboard motor runs clockwise, port motor opposite. Tabs functional. Can anyone tell me what the correct gear ratio transmission should be?

Posted: Fri Sep 23, 2011 8:00 am
by g36
have you checked timing on the engines? are they advancing fully? oem tanks?
fuel filters dirty? anti siphon on tanks partly clogged?.

mine is velvet drive 1.52:1
i have chrysler twin 318 s

Posted: Fri Sep 23, 2011 8:14 am
by RipTide
timing checks out, filters new, anti-siphon may be an issue. how do I check? Engines run normally while not under load.

Posted: Fri Sep 23, 2011 9:24 am
by g36
so your getting full adavance on the distributors?
good fuel?
could the carbs not be opening the secondaries?
copper gas lines? or rubber
anti siphon, its a ball check valve it will be mounted on top of the gas tank inline with the fuel line. mine is just before the 90 degree elbow on the fuel tank fitting when it goes into the tank. if you take it apart you will see the valve. also are these the original galvanized tanks? you could temproary bypass to see if it is the problem but i would reinstall it or purchase new for permeant

Posted: Fri Sep 23, 2011 10:07 am
by Stripermann2
Check everything as stated above. A/S valves are prone for clogging. Won't draw enough fuel under load.

I have 1.52-1 trannies and 16X16 props as standard on my 32.

Speed issue

Posted: Fri Sep 23, 2011 10:07 am
by TADTOOMUCH
What speed are you moving when at 2600 rpm's? Maybe the tachs are wrong. Is it both engines or only one? If your backflow preventer (antisiphon) check valve is plugged it would make your engine sputter and not provide a constant rpm. If you can maintain a constant rpm without the engine sputtering or misfiring then it is not a blockage in the fuel line. It is more likely bad old gas, non advancing spark, crossed spark plug wires, cracked distributor or if you have old points and condenser ignition, a bad condenser or worn points. Replace with electronic ignition parts.

If you have replaced all the fuel filters, try switching fuel selector valves so that you draw fuel from only one tank for both engines and then try it with the other tank. It is highly unlikely both antisiphon valves would be plugged so that might tell you which tank is the issue.

If you have gas in the tanks that is older than a year or so I would try to either dilute it with new gas and add some startron fuel treatment or have the old fuel pumped out and replaced.

Posted: Fri Sep 23, 2011 11:21 am
by prowlersfish
Are you sure the props shafts and runing gear are clean ? in some areas 30 days and you have a fair amout of growth and that will slow you down in a hurry

what gerar and what size props do you have ? what speed are you getting at wot ?

Posted: Fri Sep 23, 2011 2:13 pm
by jav
I agree with the others- Have you checked the running gear? What is your speed at 2600? Did you seatrial the boat before you bought it and how did it perform then? Did you load the boat up after?

Posted: Fri Sep 23, 2011 6:51 pm
by RipTide
I did seatrial the boat, motors ran smooth, compression checked out - would not pass 2200 rpm port motor and 2500 on the starboard. Great price - I bought the boat. Re-adjusted the throttle linkage, got the current 2600 RPM from each motor. Transmissions are 1.52:1, 16x16 props. bottom and gear is pristine. I am a commercial diver. I have run 2-300 gallons of fuel within the past 2-3 months, marina bought non-ethanol.
Today, upon following the advice of earlier replies I changed the check valves, removed the old antiquated fuel filters and replaced the new fuel filters again. Pumps very well. I will go out tomorrow. Wish me luck on this inexpensive "fix"!

Posted: Fri Sep 23, 2011 7:05 pm
by prowlersfish
What sort of speed are you getting ? make sure the trim tabs are not stuck or set all the way down . check the tachs also.

Good luck tomorrow

Posted: Fri Sep 23, 2011 7:50 pm
by RipTide
truthfully I am not sure, I think about 10 or 11 mph. When plowing like this I move the tabs up and down and watch the bow and wait for her to pop up. I give up pretty quick and just settle in instead of continuing to waste so much fuel.
Thanks mucho on the well wishes. Will keep you posted.

Posted: Fri Sep 23, 2011 8:45 pm
by prowlersfish
Plowing ? bow not coming up ? Look at the tabs real good may be stuck down , do you have a lot weight up front ? if you don't have a gps see if you can borrow a hand held one and see what the speed is for sure

every little clue helps

Where are you near ? maybe someone on the site is near by and can go for a ride and give you a better idea .

Posted: Fri Sep 23, 2011 9:14 pm
by RipTide
gps works fine, I just paid little attention to speed. Plowing for sure. Bow reacts as it should, rising and falling in relation to the the tabs.

Posted: Fri Sep 23, 2011 9:15 pm
by RipTide
Tarpon Springs, Fl

Posted: Fri Sep 23, 2011 9:16 pm
by RipTide
come on down, I would welcome the ride along. Lunch is on me!