Trojan Boat Forum

Hello...

I've got a 75 Trojan F25, everything runs fine, save for a little squeek now and again, I think it may be the alternator as I'm having some charging issues... but I've got a replacement on order...

I'd like to check the water pump impeller and not sure how the system is set up... Are their 2 water pumps in a 318? circulating and raw water or just one... Is the only way to check the impeller is to take off the raw water pump? I think it's on the pulley to the right in looking towards the back of the boat, anyone have a DIY?

It's a Chrysler 318

Thanks

Yes, two pumps as you mentioned. If you're pumping water out the exhaust in a good amount, you're pprobably fine. But if your pump impellar hasn't been changed in a few years, you could yank it out and replace. Give you a piece of mind.

Thanks for the reply... Just wondering if anyone had a DIY on how to take them both out? Or do I just pull the one? I'm pretty handy but need someone to tell me what to do...lol...

If it looks like this below, and you can get to the rear of the pump, remove the 5 small bolts, take the cover off, remove impellar and whala...you're done. Or, you may have to remove whole pump to get to the impellar, but piece of cake either way. The recirculation pump bolts on the front of engine if it ever leaks and you need to replace that one. It'll have a steel impellar. It usually won't need replacing unless it leaks or the bearing goes out.

Perfect... Thank you very much....

I'm assuming, the way to do it is close the seacock, get a bucket ready and start unscrewing...

Generally don't need to shut off the seacock. The hose connection is higher. But not a bad idea to get into...any water dripping out will eventually be pumped out with bilge pumps- no worries.

Some models had dual pocket pumps (two impellers). One impeller will have 2 hoses to the pump body as indicated in the parts breakdown above. Dual pocket pump will have 4 hoses on it.

Is the motor fresh water cooled (coolant/antifreeze cooled with a heat exchanger) or raw water cooler? My old raw water cooler 318 motor had the dual impeller pump which served as the raw water pump and circulating pump so there wasnt a circulating pump mounted on the front of the motor. The new freshwater cooled 318 I have in the boat has the single impeller raw water pump and a separate engine circulating pump mounted on the front of the engine. I have to to remove my raw water pump completely to inspect the impeller. Just remember how the pump is oriented on the engine and also the direction of the fins on the impeller before you take the impeller out. It gets a little confusing when you have to put it back together. May want to take pictures during each step so you have something to reference.

Do a search on here for "raw water pump" or "raw water impeller" and you should find lots of info. It's a simple task. I use vasoline to install the new impeller.

Better yet, do a search for "impeller" you'll find it faster.