HELP! 353 w502 top end problem

JimKav · 09-27-2009, 09:38 PM

Picked up a 353 last year from lake cumberland marine. Coming into marina @ marblehead the port engine died on me. Put it in neutral and tried to start it, LOUD CLANKING from top end when it started (tough to start). brought it in on one engine. What should I look for/any typical probelms w/502's top end w/300hrs on it?

JimKav · 09-28-2009, 03:00 PM

Help anyone? What should I look for one I remove the valve covers?

humbler · 09-28-2009, 03:48 PM

No firsthand expereince here, but I've seen many reports of valave spring issues on certain era 502s. Generically speaking a broken valvespring typically wouldn't result in a terrible amount of noise unless you actually had some piston to valve contact or dropped a valve. Not sure what's typical in this situation though...

eastsideoffshore · 09-28-2009, 05:11 PM

pull the plugs and check for water in cyl

JimKav · 09-28-2009, 05:15 PM

what would water in the cyclider mean?

sleek1 · 09-30-2009, 07:41 PM

Exhaust manifold leak, or reversion. These are 502s correct, not 500HP or 500EFI? I wouldn't think valve springs would be a problem on a 502.

sleek1 · 09-30-2009, 07:44 PM

Need more info. Thru transom exhaust or silent thunder? Could a wave or wake have slammed into the transom when you were coming off plane into the marina?

JimKav · 10-02-2009, 10:22 AM

Sleek,
stock 502, through hull exhaust-water could have slammed transom when comng off plane into marina. Thats when the engine died, right after I came into the channel. Going to pull valve cover's off saturday. Any idea what to look for?

tcuda499 · 10-03-2009, 10:14 PM

If you are stuck on pulling the valve covers look at all the valve springs.....make sure they all look the same,uniformed.No unusual kinks,bends,or broken springs. Also if a vavle and piston met, the valve stem could be bent and it might not move up or down. It could be wedged open so there would be a gap between the top of the valve stem(top of spring) and rocker arm when the valve should be closed. I would start with pulling the plugs,checking for water in the cylinders. If none do a compression test and go from there. It could be a littler confusing if your not into engines so I would suggest getting a buddy over for a couple beers and a little help.