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Possible timing issue

F

fishinhard

Member
165 HP 250ci. Rebuilt the engine, had the carb rebuilt and tuned for that engine. HEI dist, new everything for the most part. Set the timing at 6 deg BTC. Runs great on the trailer. Put it in the water, starts and runs perfect. Goes into gear perfect and will start to rev up. Get to WOT and it boggs down. If I back off just slightly it does ok. I advanced the timing a little and it got better. Ran it again and advanced at little more. Then the pinging started so I retarded just a little. It is not even getting on a full plain. I hooked up a vacuum advance to the manifold before doing this timing. Before that it would not go more than half throttle if I was lucky.
So is it a timing issue or does the carb need to be adjusted. I thought the adjustment screws were for idle mainly. Please help. I have soo much time an money wrapped up on this engine..:mad:
 
HEI?

sounds like it is from a car. Not only is that dangerous on a boat (not spark suppressed/ explosion screened), it probably does not have the correct advance curve for marine use.

Boats don't use vacuum advance. They use fully mechanical advance distributors.

now you know why.
 
yes for now it is from a car. The marine dist I had went to crap. I have to buy a new one. It has the screens in the bottom it is not just open. You can buy HEI marine dist.
 
The entire engine was rebuild by a local machine shop that has been around for over 25 yrs. He as done work for me before, and has done lots of marine engines. That could be an issue. He over sized my intake valves. The original ones were really bad and it was easier to over size than repair and replace.
 
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