New to the board, Question about reeds

[supergenius74]

Hello im new, I bought an old 75 johnson 135 v4 <br />last summer and rebuilt it, fixed an cleaned alot of things an now it runs and starts good. My quesion is about reeds, how do you know when they need replaced, what are the signs and how often do they need replaced. Mine looked fine but i did not replace them and I am wondering how they can affect performanc. thanks

 

[Joe Reeves]

Re: New to the board, Question about reeds

Super..... Those reeds (leaf valves) will never require replacing unless one of them breaks for some reason (very unlikely).<br /><br />Should a reed break, that cylinder will stop firing properly due to the fact that there would be no crankcase pressure existing which would be needed to force the fuel to the top of the piston.<br /><br />Also, a broken reed would allow fuel to spit out the carburetor throat with quite a force when the piston is on its downward plunge, forcing the normal crankcase pressure back out through the carburetor..... very easy problem to diagnose.

 

[supergenius74]

Re: New to the board, Question about reeds

Thanks for the reply joe, i looked them all over and cleaned them along with everything else in the motor when i re-built it last summer. I'm not haveing any major engine problems, good compression in the cyl, all between 120-125 psi. It starts good and runs good but only goes about 40-45mph @ 4000 rpm at WOT. The boat is small and light, a 73 checkmate 15' and the prop is a 13" dia but i have no idea what the pitch is, im just trying to figure out if anything is wrong because the shop manual says max rpm range is 4500-5500 and the boat also has a hell of a time getting up on plane.