correct prop?

[seantim]

i have a 16ft bass boat with a 75hp rude model#75643d won't even start to come up on plane carbs are clean 120 comp. on all 3 cyl. the prop is 13x19 i need help

 

[Dunaruna]

Re: correct prop?

You will need to find out what your wide open throttle RPMs are. You also may have a dirty bottom.<br /><br />Generally speaking, the senario usually goes like this...........<br /><br />Do a tuneup, go for a ride with a normal load of people and gear. Note your WOT RPMs. Change your prop to either raise or lower the WOT RPMs. More pitch = higher RPMs, less pitch = lower RPMs.<br /><br />I just read your other threads, probably a good idea to make sure the carby butterflies are fully open when throttle is maxed out.<br /><br />Aldo

 

[seantim]

Re: correct prop?

sorry i can't check the rpm's i can't get it to move much past idle i took the carbs back off and they seem to be clean and clear when i go to wot it just boggs

 

[Dunaruna]

Re: correct prop?

You've had the throttle box apart, yeah? With the motor OFF, push the lever all the way down then check your carby butterflies - are they fully open?

 

[seantim]

Re: correct prop?

yes carbs are fully open whet box is at wot

 

[Dunaruna]

Re: correct prop?

Originally posted by seantim:<br /> sorry i can't check the rpm's i can't get it to move much past idle

I don't think that the prop is your problem. Maybe someone else here, with carby experience, can advise further.<br /><br />Does it rev o/k in neutral (don't max it out)?<br /><br />Aldo

 

[Goodoleboy]

Re: correct prop?

Hi Seantim!<br /><br />If it were my motor I would do a link and sink procdure first thing. <br /><br />Second check timeing at idel, should be something like 4 degres btc.<br /><br />I then would take carbs apart again, completly apart includeing removeing welch plugs. soak all metal parts in carb cleaner, no plastic or rubber in carb cleaner.<br /><br />Blow all passages clear with compresed air. reassemble carefuly make sure new gaskets do not cover any passages, no ragged threds hanging to gaskets.<br /><br />With 120 pounds compresion on all three cylinders this engine should run good as brand new.<br /><br />Check carefuly all hoses comeing from fuel tank all the way to each carb for lose connections or cracks you have to take hold of them wiggle and pull, looking at them dosent do much.<br /><br />Hope this helps...good luck!

 

[Goodoleboy]

Re: correct prop?

Hi seantim!<br /><br />I misspoke when I said timeing at idel should be something like 4 Degres btc. I had four degres in my head from a driffrent procdure.<br /><br />Follow the Joe Reeves procdure for seting timeing at idel. It works Ive tried it on my forty horse.<br /><br />you can find his procdure here on the forum.<br /><br />Sorry about that!

 

[mjash]

Re: correct prop?

Did you verify spark @ all 3 cylinders...Sounds like one is not firing

 

[seantim]

Re: correct prop?

seems to have great spark it will jump an inch or better