sick ST350/ low compression

[G1159boy]

Hi guys, my workhorse is sick and I need some advice. Here are the symptoms. Dry compression is 120 and 115. Wet is 180 and 180. Valves are set at .004 with blow back out the carb at low rpm.
What should I overhaul (rings, valves, ect.) and any guesstamation what I can expect to pay for parts.

Thanks for your help.

dave p

[BLUE72CAMARO]

Does the engine smoke when it runs?

With the blow back out through the carb it sounds like you valves maybe shot to me. You can buy upgraded valves and springs for around $100 and then you will have to have the valve seats done on the head as well but that shouldnt be very expensive.

[supergolfer]

For what it is worth I just rebuilt a 2002 ST350 Workhorse. I replaced all seals, rings, valves, valve springs and valve seals. I did follow a pretty standard procedure for lapping in the valves. I also replaced the pulsar coil and coil as I only knew the engine had one dead cylinder when I received the unit. After all was said and done, the engine runs great and was well worth the rebuild (considering I got the unit for free)!

[G1159boy]

Last night I pulled the engine and today I broke it down.
Intake valves seem to be the problem, but i noticed some other stuff. Cam lobes are not uniform anymore and two of the rocker arms were quite worn. see picture. Is the worn cam a huge deal (I know what your going to say)? I dont really want to spend 300.00 on a new cam if i dont have to.

[supergolfer]

G1159, my cam lobes and rocker lobes looked identical and my unit is running great! I would not pay much mind to it however, I will make sure that I change the oil on a regular basis. My workhorse came off of hard use on construction sites and was not taken care of very well, hence the reason I got it for free and have done a total rebuild. Good luck..