Trojan Boat Forum

I just went in the water (yeah!!) All good, but water temp on starboard engine was a little higher than normal--and not as much water coming out of the exhaust as usual either. I replaced the impellers on both engines--they were starting to come apart. Starboard engine water temp and flow is great, but now the port engine doesn't get above 100. Water flow is good & the engine is cool to the touch. The temp guage was working when I put it in; I cleaned the contacts on the sending units--although they looked good before...the needle does go to 0 when I shut it down. I didn't try it from the bridge yet--all from the lower station...

what should I do for the next step?

Check your hose connections that you disturbed, the new impellers pull pretty good and maybe pulling air on the side with less flow than before.....did you get all the pieces of your old impellers out ??...Mike

Did you change the thermostat? Any time where I have had trouble UNDER heating, in any vehicle, it was the thermostat. if no, it's a cheap and easy maintenance item. If yes, perhaps you have the gasket misplaced. There is usually a small pin hole in the thermostat housing that allows air bubbles to pass.

If all of that is in good nik, then I would look at the temp sensors.

bjanakos wrote:Any time where I have had trouble UNDER heating, in any vehicle, it was the thermostat.

+1 A small piece of debris could keep the thermostat from closing completely allowing coolant to flow right thru without ever coming up to temp. Being a Lake Erie boat, I'm assuming that you have an open (raw water) cooling system?

Right, open raw water cooling--I got all the debris out I found, but you never know. I had an impeller "blow up" on my old 31' and had to take all the hoses off 5 or 6 times to get all the debris after putting the new impeller in, but it wanted to overheat, not underheat--I'd find a couple pieces, put it back together, fire it up watch the needle go up...take it apart again, more pieces....I got pretty quick at pulling the impeller!!

I'll check the thermostat first--maybe some debris there--I assume it was working before I replaced the impeller because it was getting a little hotter than ususal.

I'm sure the hose fittings are tight--but when I went to change the impeller, one wasn't. I pull a hose to pump my antifreeze in when winterizing and aparently didn't finish putting it back together. I was thinking that might have been why it was running hotter when I started it and not pumping as much water through--probably pulling in some air?

adrewoh wrote: I was thinking that might have been why it was running hotter when I started it and not pumping as much water through--probably pulling in some air?

Might have a bit of air lock. it happened to my on my previous bout just about every year....

Sometimes goosing the throttle a bit will suck in enough water to create a good vacuum. Also squeezing the large coolant hose while the motor is running to "burp" the air out of the system.

Got the new thermostat in, all good! Thanks! If it was all this easy....

my crusaders are doing the same thing, with new t-stats, my first check is to switch the gauge wires and see what I get. If same it will be the temp sensor I think. Engines have new impellers, new t-stats. temp difference is 140 on port and 155 on starboard.