View single post by vnavaret
 Posted: 12-18-2023 08:08 pm
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vnavaret



Joined: 04-07-2022
Location: Oregon USA
Posts: 54
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Esprit2 wrote: So the Temperature Compensators are an alternative. A bi-metallic strip opens & closes a port in response to ambient temperatures. The result is an emissions-friendly mixture for warmer seasons, and an automatically adjusted cold-friendly mixture during the frigid Winter months. Since most J-H don't get driven in the Winter (no Florida... a 'real' Winter), the Temperature Compensator isn't really required, and it's just something else that can fail and cause problems. Regards,Tim Enge

I wanted to offer an alternative explanation for the temperature compensator, despite the fact that this is a very old thread. If you permanently close the temp compensator, as Tim suggests, you are very likely to run into hot start difficulties, especially 20-30 minutes after shutting off the engine.

The carburetors heat soak during that time. When attempting to start the car, air being drawn through the carburetor is heated appreciably, and is therefor much less dense, so the mixture goes super rich - carbs add fuel based on air volume, not air density. If you manage to get the car started, it will run poorly for a minute or two until the incoming air cools the carb sufficiently. This is especially true if the carbs have been tweaked to run with a rich mixture in the first place, as many owners seem to prefer.

The compensator solves this by leaning the mixture when the carb is hot, thus the car starts normally. When the carb cools after a minute or two, the compensator closes, returning the mixture to normal. I urge JH owners to NOT defeat the temperature compensator lest they induce hot start issues. This may defy the conventional wisdom, but I assure you this is correct.

If you are having the hot start problem, get your mixture correct by using a color tune or plug cuts. Still having problems? Your compensators need to be adjusted back to their factory settings.

Vance

Last edited on 05-15-2024 04:33 pm by vnavaret