Trojan Boat Forum

Can anyone look at this photo and tell me if they have a different pulley size for the raw water pump or crank? I have a theory that they are wrong diameter and not spinning the pump quickly enough. Engines are fine at cruise but get hot over 3000 RPM.



Thanks,

Chris

I can't, but I can tell you that about 90% of the time, its that the impeller inside the pump needs to be changed. Its a simple task, and typically, they need to be replaced every-other year (some recommend yearly, just so you don't have problems). I've had all sorts of symptoms at high and low RPMs with temp variation that were solved with a new impellers. They cost < $30 and take only about 20 minutes to tear down, insert the new one, and re-assemble.

What you picture is the engine water pump and what you need to repair is the raw water pump that is driven by a fan belt. Like LandV said, a worn or broken impeller in the raw water pump will make the engine overheat. here is a pic of mine off a 351 Merc.

Thanks, but after trying new impellers and cams, I put in brand new sherwood e35 pumps, so that isn't the issue.

In the last 2 weeks, the boat has gotten new manifolds, risers and elbows and the heat exchangers have been boiled, refurbished and pressure tested.

Basically, there is nothing left to change out but the pickups, the oil coolers and exhaust. I'm not worried about the oil coolers or exhaust since they flow really well.

That's why I'm looking for stuff like wrong pulleys.

Thanks for the suggestions - I'd love for someone to take a look at their engine and tell me if the cam size looks the same.

(edited, was using cams, should have used the word pulleys)

Sorry, I know that photo isn't exactly on the pump, but it's the best one I've got and I think works for estimating pulley size.

Its not the pulleys .check the thru hull and and valve for restriction also clean out all your cooler s , (trans and oil etc) if freshwater cooled make sure the antifreeze is not stronger then 50/50 .

Thanks prowlerfish, good stuff. I'm planning to haul out next week to do props and will check thru hulls and valves then. I was planning on just removing the hose at the seacock and inspecting the inside and the strainer from the outside. I should be able to see light through it, right? Any other tips for checking for restriction? Not possible to do this in the water, correct?

Re: the trans and oil cooler, it's a U shaped one as you can see in the photo. I've taken the hoses off and blown through the cooler (hand coupling ), water flow was good. Not sure what else to do with them to clean them out - any advice?

I've also blown air from the pump output hose out the exhaust and was suprised how easy it was. There doesn't seem to be much / any restriction in the whole system post pump.

Also re: antifreeze it's all new as the mechanic replaced the manifolds. I'm sure he mixed it right but it's worth a check...

Prowlerfish is right, when I first got my F-32 I hauled the boat for bottom paint and found the pickup screens on the bottom of the boat were smashed in and had been painted over several times blocking the water flow. This explained the rise in engine temperatures while running at higher speeds. After opening up, cleaning off the paint between the grates and spreading the grating on the pickup screens the water flow increased triple and the temperatures remained low and constant at all speeds.

i had the same isue with the pick ups with the years of paint allso do you have strainers if so have you checked the screens allso now this mite be for seperation on the inside hoses mite be calapsing under higher suction i have seen this happen

Question: Can I temporarily bypass the oil & trans cooler to make sure that isn't creating a blockage? I'm pretty sure I can run that way at the dock, just to check for flow from the exhaust, but can I go take a few speed runs with it out of the loop?

Thanks!

I would not . You can clean your cooler and the raw water side of your heat exchanger with rydlyme . also look for sea weed in the cooler and blades off the impeler .


http://www.rydlymemarine.com/

Not a direct reply to your question, but you have a nice and clean engine room that looks well maintiained

If you'd like, I will measure mine and get back to you. My pulley that is.!!

gettaway -> Thanks, the PO was pretty into keeping things clean.

foofer b -> . Please remember that pulleys are measured in diameter, not length.

foofer b wrote:If you'd like, I will measure mine and get back to you. My pulley that is.!!

Yea let us know what size pulley you have lol