Jeep problem HELP!

[fayjo56]

My GPW is not running right. On tickover it gives the impression from the exhaust of running rich, on high revs under load on hills etc there is a very noticeable misfire. I have changed the Distributor cap, leads and plugs and it has a breakerless point conversion. I have now put on a new carb to no avail. A compression test has shown up a drop in compression on no2 cylinder (down to about 70psi) removal of this HT lead on tickover seems to make no difference. Any suggestions on what the problem might be please?:confused:

[Swill1952xs]

My GPW is not running right. On tickover it gives the impression from the exhaust of running rich, on high revs under load on hills etc there is a very noticeable misfire. I have changed the Distributor cap, leads and plugs and it has a breakerless point conversion. I have now put on a new carb to no avail. A compression test has shown up a drop in compression on no2 cylinder (down to about 70psi) removal of this HT lead on tickover seems to make no difference. Any suggestions on what the problem might be please?:confused:

 

Not an expert on Jeeps, but 70psi aint good. I would imagine an engine of that age should have a compression pressure of around 120psi. (Modern engines are nearer 150psi) A drop in pressure on one cylinder will make it appear to run rich as the others are trying to compensate for the imbalance.

 

Jus' tryin' ta be helpful. :-D ........ Now I'll let the people who really know what they are talking about answer the question.

[Richard Farrant]

A compression test has shown up a drop in compression on no2 cylinder (down to about 70psi) removal of this HT lead on tickover seems to make no difference. Any suggestions on what the problem might be please?:confused:

 

Check the valve clearance on No2 cylinder, most probably the exhaust valve clearance has tightened up. It may improve by readjusting, but might now have burning on the face and seat, and require attention.

[fayjo56]

Thanks chaps, looks like you were right Richard. There is no clearance at the tappet and there was neat fuel in that exhaust port. Thankfully the valve seat still looks in excellent condition although I think I will lap it in anyway.:yay:

[Richard Farrant]

Thanks chaps, looks like you were right Richard. There is no clearance at the tappet and there was neat fuel in that exhaust port. Thankfully the valve seat still looks in excellent condition although I think I will lap it in anyway.:yay:

 

Great, hope all is well once you have done that. :thumbsup: