SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: smb123 on June 22, 2015, 08:56:29 AM
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Hi all I know this has been covered I was hoping to get some of your guys set ups for the exhaust plumbing that your running to fight this issue.
My friend is running a comp cams thumpr cam :banghead: :banghead: 107lsa 291/311 dur.235/249 @.50 http://www.summitracing.com/parts/cca-11-601-8/overview/make/chevrolet (http://www.summitracing.com/parts/cca-11-601-8/overview/make/chevrolet) and im thinking we have water revision, I know poor choice in cam, wish we had done more reading into it.
We took the boat out for its first run with the new motor and it ran great, idled at 800-1000rpm and ran strong, the next time we ran it it wouldn't idle for crap, it always stuck at 1800rpm. this continued the next time out so we started trying to tune it, we worked on the carb and went through it and checked the needle valves, power valve and so on. we also tried to adjust it with the dist. and same thing, no matter what we did it would stick at 1800rpm, it also wouldn't matter where the idle screw was at it would stick right their. I'm thinking we blew the head gasket to begin with and just didn't realize it until this last weekend. He's running rewarder twist wet headers and its plumbed off the top water neck (pass. side outlet) and goes into a T fitting and then to the headers.
I'm looking for ideas of how to plumb the system so that we wont have a water revision issue, we'd run them dry and just take our chances but we don't want to blue the headers since their chrome. any advice and input would be great. thanks guys, again sorry I know this has been covered before.
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If it won't idle below 1800 no matter what you do to the carb and dist... I'd be looking for a vacuum leak. That cam is not the best choice, there is much to be gained by a cam change alone... but you really shouldn't have a reversion problem if you keep the idle up above 1000-1100, manually turn the water on and off when on plane (not idling around), and restrict the water down to a nice mist instead of pouring out of the headers. With the right setup... I've run as much as 96 degrees of overlap and not had reversion problems... at about 100 I've not had a problem, but the signs were apparent... but if you were to run it just with a bassett t valve and let the water flow like crazy, for sure would have problems.