1991 140 v4 is it a stuck reed?

[medburd]

Hi folks I need your help. I have a 1991 vro 140 johnson that has great compression 125 for all cyl. gets spark on all cyl. but isn't firing on one of the cylinders. That cylinder like I said has strong spark and the motor ran great when I winterized it. Now I'm taking it out of storage and I found this...could it be a stuck reed? can it be unstuck or is it broken? if it is broken what would the typical repairs for something like this go for? would you suggest I try some sort of other testing...or do you think it is something else? any help is appreciated...<br />thanks<br />medburd

 

[OBJ]

Re: 1991 140 v4 is it a stuck reed?

I gotta' ask medburd, how do you know it's not firing on the in question cylinder? Which cylinder is it? Are you seeing a reduction in WOT rpm? Plug dry? Need a little more info.

 

[medburd]

Re: 1991 140 v4 is it a stuck reed?

I ground out the plug wire on the number 3 cylinder and it has no affect on how it runs. If I leave the wire off that cylinder it runs the same. I haven't dropped it in the water yet...and the plug looks like the rest of them..a little wet...when you ground the other cylinders the rpm is affected.

 

[OBJ]

Re: 1991 140 v4 is it a stuck reed?

Swap your number 1 and 3 ignition coils. If the problem follows, coil is bad.

 

[G DANE]

Re: 1991 140 v4 is it a stuck reed?

A weak coil can spark in open air, but in combustion chamber where gas fumes isolate it takes a stronger current to make spark jump. Thats why spark testing involves to let the spark jump a 3/8 or 5/16 gap in open air, a healthy coil will do it with a snap. Reed failures are rare, but shows up. The big question isnt replacing the reed leaves, but where the broken leaf is, if it isnt just bent, Is it sitting inside motor waiting to fly out and detonate a piston ?

 

[medburd]

Re: 1991 140 v4 is it a stuck reed?

thanks for this folks..I'll give it a shot this week when time allows and let you guys know what happens.