Reed Valves - Johnson V4 - Quick Question

[jerjag]

Quick question - Is it possible for reed valves to stop working properly when the motor reaches temp or it is the case of either they work all the time or none of the time??<br />(Motor is a 1971 Johnson 100 V4)

 

[Steve135]

Re: Reed Valves - Johnson V4 - Quick Question

What makes you suspect them? Is there not vacume after the motor warms up? You could check it out with your hand on the carbs one at a time if the motor changes with the covering of each then they are probally good if there isn't any noticeable change then you could have a bad set?<br />steve

 

[OBJ]

Re: Reed Valves - Johnson V4 - Quick Question

Another way jerjag is to look for blow back out the carb. This happens at low rpms and is noticable by the extra fuel laying in the pan. The engine may not idle worth a hoot but may run pretty decent on top end.<br /><br />I'm curious like stinky....what makes you suspect them?

 

[jerjag]

Re: Reed Valves - Johnson V4 - Quick Question

Motor will die after 5 or 6 minutes and will not start up for around 15 minutes. It will only start at full choke and at high speed. Engine will not idle. I suspect a fuel related problem. Pump is new and I just finished rebuilding the carbs. (Both floats were out of adjustment). As long as I had the carbs off I thought about the reed valves, but I'm not that familiar with their operation, or if they could be contributing to my problem.<br />Thank you for responding!!

 

[DHPMARINE]

Re: Reed Valves - Johnson V4 - Quick Question

jerjag basically reeds open as your piston goes up the cylinder,and close when the piston goes down.If they stick open fuel will spray out of the carb as the piston comes back down.<br />I suppose it could happen,but I've never see a reed stuck shut. Well maybe when a connecting rod comes loose,but I don't think that's your problem.<br />DHP<br />When the motor quits,have you tried squeezing the primer bulb?

 

[OBJ]

Re: Reed Valves - Johnson V4 - Quick Question

jerjag....there are several things that can cause your problem.<br /><br />Have you checked compression lately?<br /><br />Is the engine overheating? <br /><br />Did you do a sync and link along with the carb rebuild?<br /><br />What kind of spark do you have?<br /><br />Points and distributor good?<br /><br />Do you have a manual? This would help you more than anything.

 

[jerjag]

Re: Reed Valves - Johnson V4 - Quick Question

Thanks for all the input DHPMarine & OBJ!! In answer to DHP - yes, I have tried squeezing the bulb but it doesn't seem to make a difference in starting. I still have to wait for the motor to cool before trying to start. In answer to OBJ - Compression is within 5% difference in all cylinders (100 - 103), motor is not overheating (no alarm), Sync & link will happen when I install carbs this weekend. Spark, to me is questionable; I grounded sparkplug on motor block didn't see any spark yet the engine would fire.<br />Motor has CD Breakerless ignition but I'm going to remove the flywheel to check everything. I have an old manual which is invaluable in getter this 'old girl' running. Thanks again for your help - any thoughts or tips would be appreciated!

 

[stairliftoheaven]

Re: Reed Valves - Johnson V4 - Quick Question

have you checked for sparks on each plug when motor is in non running phase? i suspect powerpack problem, you might be not running on all cylinders at low revs. Faulty semiconductors are fickle things: can be fine when cold, give up when warm and be fine when cooled down again. Can't imagine reed valves are the problem here

 

[captain spike]

Re: Reed Valves - Johnson V4 - Quick Question

sounds like powerpack failure <br /> <br /> <br /> ***1971 winner 1969 115 jonny***

 

[Toontime]

Re: Reed Valves - Johnson V4 - Quick Question

heat related electrical problem.