Hi Charles
The actual R & R of the valve covers was easy enough and the cleaning of the drain holes was a no brainer, but to get at
the covers to take them off my boat engines would be a rather large undertaking. The van engine wasn't too bad. I have
no idea if you can still buy brand new carburetors or not, it may be an option. I had considered buying a brand new
Holley back in 1980 but decided to go with the "Factory Fresh GM Rebuilt", which was junk. Apparently the most
noticeable symptom of plugged drain holes was the puff of blue smoke that would come out of the exhaust pipe when I
started the Van after it had sat for a while. I don't think I could see that on my I/O's but you might on your inboard.
Just guessing.
I would mention my experience to your mechanic to get his opinion.
Good luck and have a great long weekend.
Kevin

Charles T. Low wrote:
Thanks, Kevin,

I'm considering having the carb rebuilt, but have been warned that sometimes
it ends up worse, even in experienced hands - or that such bad damage is
found inside that it can't be salvaged.

Something like what you're suggesting makes sense ... I just have never
personally looked into the guts of an engine enough to know quite exactly
what you mean. But is the kind of thing you're suggesting something for
mechanic, or could anybody do it? It seems to me that unbolting the covers
and having a look wouldn't be beyond the average person's capability. Then
you would need a gasket kit to put it all back together?

Charles

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Charles T. Low
www.boatdocking.com

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"Kevin & Debbie" wrote in message
...

Hi Charles,
I once owned a 1977 GMC van with a 350 carbureted engine. I bought it
(ab)used and it used 1 quart of oil for 500 miles, I started using 20W-50
oil as the back plugs would foul with oil in the course of about 5000
miles, and I would have to pull them and clean them. It also would run
rough if it was idled too much and would clear up once out on the highway.
I pulled the valve covers and found oil sitting there. The problem was the
oil drain holes in the head were plugged and the oil was going down the
valve stems into the piston chambers. I plunged out the holes with a coat
hanger and the entire problem went away. I then got over 2000 miles to a
quart of 10W-30 and the plugs never fouled again.
On this same vehicle I installed a GM professionally rebuilt carburetor
and then immediately had to have it repaired/rebuilt by a local small
engine place, who put the proper Power valve spring in.
FWIW.
Kevin