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Old 11-12-2018, 05:48 PM
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Quote:
Originally Posted by Dave Neptune View Post
Joe, I agree that the heat is no big deal. It is the temp of the box that is the concern. You probably were in the early stages of "vapor lock" conditions. Vapor in the pump will not pump thus the zero.

Do you have any idea how hot the engine compartment was? Do you run the blower to keep the box ventilated?

I assume you are running in fresh water.

I did a re-plumb of the bypass line and had far more consistent control of engine temp and I could trust the gage much more. I posted some pics a few years back I think. I did this all without any t'stat. In fact when I bought the boat with the seized engine I removed the t'stat while getting it running. Just might work for your experiments as far as temp control and accurate reading are concerned.

Dave Neptune
I also removed the thermostat and have a bypass valve. In RWC mode it works great, i can keep the engine below 120 if desired even on the hottest day unless I run 100% power. I might creep up to 130.
In FWC mode not so much. It will be at 160 even at moderate cruise and head right for 180 or more at full blast.
The engine "room" is not roomy and gets quite hot if the engine is at 180. I agree vapor lock is the issue and it would have been next to impossible to find out without a fuel pressure gauge.
* not sure about the boat being in fresh water. This year kind of we got so much rain but usually it is salt water here. The dolphins that jumped around me on the 4th of July died from some fresh water issue about a month later
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