J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Adding a temp gauge - 2GMF with B-panel

I agree on the metric thread analogy for the temp sensor. Even though the block was made by General Motors (hence the 2GM moniker), the balance of the parts are designed & built by Yanmar using metric standards. Both standards are used on the engine, although the fasteners are predominantly metric. The socket set I keep on Rhapsody has both metric and SAE sizes to accommodate both. I highly recommend picking up something like a 24 piece SAE/Metric socket set and leaving it on the boat with other "emergency" tools. These have saved my bacon more than once when a needed repair was made underway, or while cruising.

I agree the in-line is not perfect but I searched everywhere and could not get a sensor that fit. Here is my rational for plan B - in-line. I had overheating issues and I wanted a guage to tell me if the temp was going DOWN once it overheated. The in-line does this. I knew temp guages are not accurate but just really wanted to know that the temp was going down - I really do not care that it drops from 120-110 or it shows 100-90 the fact that it is dropping is what I was concerned with.

Well I did a bunch of other work on the cooling system and thankfully I have not overheated since (-: so I have not been able to really use my guage.

David
#397

Sounds like you may have sucked something up the intake. I sucked a plastic bag over the intake grill once and it did a very similar thing.

David
#397

Good point David. And it does work in that sense. I havent overheated again yet (like you, I did some other stuff at the same time), but for example, If I'm running for a while and then throttle down, I will see the temp bump up from the low RPMs, then settle back down - so it is definately giving me useful information.

-dan

Dan - I had the same symptoms before I cleaned out the water passages in the head. The front cylinder was pretty much scaled up, and in some spots the scale had turned to hard carbon blocking the passages. I had virtually no water flow around it before the cleaning. I'd get the high temp alarm after slowing down subsequent to running higher speeds. The reduced flow from the water pump at lower RPM wasn't enough to take care of the heat that had built up.

I know you're fresh water cooled, but consider taking off the manifold that the thermostat screws into and see if there is any obvious build-up/blockage there. You also may want to check the thermostat and make sure it opens in a cup of boiling water.

Second thing I found after I rebuilt the engine was the water pump bearing going bad and finally seized. I replaced the pump and have noticed significant improvement in the water flow out the exhaust spray. I rebuilt the old pump and include it in a bag with my "cruising spares".