reed Valve

[Mac]

What are the symptoms of a defective Reed Valve?

[DaveR]

If it's carbed, it'll spit gas back out the carb. My EFI hasn't had the problem yet, but I imagine it'll do the same. Idle won' be very good either.

[us1]

Also it is hard to start and will backfire through the carbs or EFI intake.

[Mac]

Thanks for the replies, bought the motor 10 years ago never has ran good, it is a 83 150 mercury, has 140 lbs comression, acts like the timing isn't advancing properly, very slow on take off, once the rpm gets up runs fair, but at times will drop from 5200 rpm to 4200 then back and sometimes it will not get but 4200 carbs checked, timing checked, check valves and tubing replaced. Ready to used it for an anchor....Had not considered the reed valves until I got to this site...Does it have to be dismantled to check or adj. the reed valves?

Thanks Again

[us1]

You will have to pull the intake manifold off to get to the reeds. The stock reeds are steel and don’t break often at 6000 RPM and under. If a steel reed does break it will do damage as it goes through the motor. Put a timing light on each cylinder a take the RPM up to 4000 while looking at the timing light. See if you are loosing fire on a cylinder in that RPM range.