Trojan Boat Forum

Well I changed my raw water pump impeller to a Globe Impeller. You are supposed to be able to run the impellers dry for up to 15 minutes with out harm to the impeller. I'm sure the engine wouldn't like that though. Anyways. Took the boat out for a quick spin after setting the timing after switching to a electronic ignition pickup instead of points (the first time running it with the new impeller). She ran great. On the way back in I got her up to 3600 rpms at WOT, bottoms a little dirty. Coming of plane the exhaust sound changed. Then the temperature started climbing. Turned off the motor and checked it with a infared temp gun. Sure enough running hot. We started it and stopped it about 5 times to get it to a dock without the temp getting over 230 degrees. There I pulled the raw water pump and sure enough the impeller wasn't spinning. The shaft key edges rounded some also. The globe impeller has a composite core, not metal like the Sherwood impellers. Sure enough the key slot was stripped and the impeller core was cracked, so the pump shaft was spinning without the impeller turning. Changed out the impeller to the older one (Sherwood brand) and still had enough bite on the key to lock it in. Was able to get back to my slip without problems after that. So lesson learned. No aftermarket parts for critical items, like impellers.

Also, you might want to change out the key next time you switch out your impellers.

Thanks for letting us know. I've thought about trying the run dry impellers but I'm glad I stuck with the Sherwoods.

good info to have , Thanks!

no first hand experience here, but I heard they were narrower (in my genny application)

led to less than adequate flow rate.

RWS

RWS wrote:no first hand experience here, but I heard they were narrower (in my genny application)

led to less than adequate flow rate.

RWS

Heard the had the same issues in Cummins .