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wadanoli · 21-04-2008, 14:00

Hello ALL,
My Yanmar 4jHBE temp meter has stayed steady for all the years I have owned my 42 Catalina. Last week I notice that, 1. When I turn on the key my meter sometimes acts funny pegging and then jump around and then settled down.
Last week I went aground and stirred up a lot of dirt shortly before anchoring. The next day I did notice my temp meter was reading very hot so I slowed down and the temp moderated but not enough to my satisfaction. I anchored again and changed my thermostat and continued on (I have yet to test the old Thermostat to see if it is still good). The temp moderated even more, so I proceeded at a slower speed and the meter would move between normal (Which I think is 160F / 65C) and about 10 degrees above and back. I then changed the impeller (which the old one looked good). My Temp meter seems to still be about 10 degrees about what it should be. I was going to give my heat exchanger an acid wash and when I removed the antifreeze I could see my fresh water side of the heat exchanger was very clean and was contemplating pouring an acid wash through the saltwater side. I was wondering if anyone knew the normal temp for a Yanmar 4JHBE. I was also wondering if anyone had used and acid wash called ZIP (hydrochloric acid)?
Any information would be very helpful.
Dave

**Hud3** · 21-04-2008, 15:52

Before you go too far, check to see if your start battery is good. When it fails, the engine instrument panel goes bonkers.

DeepFrz · 21-04-2008, 18:54

Did you clean the strainer? Are you getting the normal amount of water out of your exhaust outlet?

wadanoli · 21-04-2008, 18:59

thanks for the suggestions. Yes I have checked both the sea strainer (that was the first thing) and the Battery I load tested today. Thanks. Do you know what normal temp is?

**Alan Wheeler** · 21-04-2008, 23:47

First off, if you had an erratic dial needle to begin with, I would check the electrical connections at the gauge and at the temp sender. Then I would test or replace the Temp sender before going any further with acid washing the heat exchanger.