Westerbeke W40 overheating under load

[er9]

an earlier poster recommended checking the water flow at the exit of the water pump">raw water pump and exhaust. i didn't read in any of your replies that you did and you mention high pressure raw water out the exhaust.



you can clean the entire raw water system and think its all good and clean but have a plugged / partially closed thru hull valve or a partially clogged elbow coming off the strainer basket. pulling a hose and testing the water flow rate will give you a good indication if there is an obstruction before or after heat exchanger.



i did all the same things to my raw water side. still had marginal, slightly pressurized raw water flow. see page two of this thread to see what the inside of my strainer elbow looked like even though i boiled my heat exchanger, dilligently cleaned my strainer and replaced every hose in that system.

its a quick and easy test to eliminate a potential source.

https://www.cruisersforum.com/forums...-237916-2.html

[Poche]

Originally Posted by Dylancs

I’m currently running the engine and now I’m at 190F at 1800RPM.

I agree it's too hot. Does the reservoir get that hot?
You should have a good flow coming out of the exhaust, also.
Mine will run about 170F and rise a few degrees with load.

[Cheechako]

Does it go over 190 degrees? Seems to me 190 is not a problem. They design today's engine to run hotter than that... better performance...

[Poche]

I was thinking that 190F isn't really all that hot, either. I don't know if anyone brought up checking the thermostat. A friend was sold the wrong one. Maybe try running without one and see what happens.

[Cheechako]

Originally Posted by Poche

I was thinking that 190F isn't really all that hot, either. I don't know if anyone brought up checking the thermostat. A friend was sold the wrong one. Maybe try running without one and see what happens.

Don't the new Yanmar's etc run over 200 degrees?

[Poche]

Originally Posted by Cheechako

Don't the new Yanmar's etc run over 200 degrees?

Not sure about the newer Yanmars. My W40 was put together about 50 years ago. Great engine but not even as modern as the 4-108's. Runs like a champ, though. The only thing is it leaks a little oil but I keep an absorbent pad under it and in the bilge.

[jimbunyard]

Originally Posted by Dylancs

Thanks again for all the helpful suggestions. I’m currently out on the boat for a couple of weeks with limited internet. My HE is stock but not the original. It’s a Westerbeke 14129CN. It’s 3” x 15”. Maybe Westerbeke put larger HE’s on the W40 than was stock on the Perkins 4-107?
I was hoping that changing the coolant pressure cap from 0psi to 15psi would make a difference. Nothing. At least there’s protecting from premature boiling.

I’m currently running the engine and now I’m at 190F at 1800RPM. The overheating is proportional to engine rpm. It seems like the more I try it fix, the worse it gets. The only consistent solution I’ve found is to not run the engine at all. Works like a charm every time. It really does not seem to matter what I do, it runs hot. I’m going to have to look at replacing the exhaust. I’m going to pull the exhaust apart to see if there are any obstructions in it. There is good flow coming out but it seems like it pressurized when it comes out. More of a spray. I’ll check that when I get to my destination today. Maybe some creature crawled up there and died.
Then I’ll look at bypassing various coolers to see if that makes a difference and go from there.

Just as a reference, my 41 cubic inch displacement engine has a 1.5" exhaust system.

You're trying to run a 107 cubic inch engine with the same size exhaust; it's not surprising that the exhaust is spraying out. With the seawater flow improvements you've made, there's likely even less room for exhaust in the ex hose...

If you change the exhaust, depending on the run, it might be advantageous to go up a bit more in size, maybe to 2 1/4", especially if the cost is negligible.

Though the difference between 1.5" (1.76 cu") and 2" (3.14 cu") is substantial, 2 1/4" more than doubles the area, to 3.97 cu", which might be seen as more in keeping with standard practices.


Out of curiosity, what speed are you getting at 1800 rpm?

Also, as Doug advises, definitely check and see if the tstat is operational, or even present. It's not too uncommon for well-intentioned but misinformed people to remove them in an effort to 'cure' overheating.

[Cheechako]

Originally Posted by jimbunyard

Just as a reference, my 41 cubic inch displacement engine has a 1.5" exhaust system.

You're trying to run a 107 cubic inch engine with the same size exhaust; it's not surprising that the exhaust is spraying out. With the seawater flow improvements you've made, there's likely even less room for exhaust in the ex hose...

If you change the exhaust, depending on the run, it might be advantageous to go up a bit more in size, maybe to 2 1/4", especially if the cost is negligible.

Though the difference between 1.5" (1.76 cu") and 2" (3.14 cu") is substantial, 2 1/4" more than doubles the area, to 3.97 cu", which might be seen as more in keeping with standard practices.


Out of curiosity, what speed are you getting at 1800 rpm?

Also, as Doug advises, definitely check and see if the tstat is operational, or even present. It's not too uncommon for well-intentioned but misinformed people to remove them in an effort to 'cure' overheating.

His exhaust is only 1.5"? Wow I missed that. Yeah that's small.

From a 4 cyl Yanmar manual: "Normal operating temperature is 169-194 degrees"

[Poche]

Originally Posted by Cheechako

His exhaust is only 1.5"? Wow I missed that. Yeah that's small.

From a 4 cyl Yanmar manual: "Normal operating temperature is 169-194 degrees"

That sounds about right for my W40 but I think it would be working really hard to get up above 180F.

[jimbunyard]

Originally Posted by jimbunyard

...Though the difference between 1.5" (1.76 cu") and 2" (3.14 cu") is substantial, 2 1/4" more than doubles the area, to 3.97 cu" ...

Oops, 'cu" ' should be 'sq" '. Duh.

[Dylancs]

This is my third attempt at replying with limited internet.

The temperature increases linearly with rpm increase. The highest I’ve let it go was 210F at 3000rpm but it was still increasing. It always cools back down to 180F by about 1700rpm. The thermostat was one of the first things I replaced. It opens at 180F as it should.

When I bought the boat and saw the exhaust size, I was surprised. On my previous boat, I converted it from an Atomic 4 to a Yanmar 2GMF. I installed a 1.5” exhaust as per the manual. The Westerbeke is twice the size. The 1.5” section after the muffler is about 8’. My math tells me increasing to 2” is an 80% increase in volume. Maybe when the engine was new and running optimally the smaller exhaust size was sufficient. I haven’t check the raw water flow but I will attempt this when I’m back from my trip.

The Westerbeke W40 manual I have shows the max rpm is 3000. At 1800rpm I can do about 5.5kts. Theoretical hull speed is just under 7kts. I wouldn’t be surprised if the prop is over pitched. The PO said there was a feathering prop on it when he bought it but he didn’t like the noise it made so he replaced it.

Regarding the brass fittings, the hose coming from the head and returning to the HE are for the water heater. I intentionally reduced the 1/2” npt fitting to 1/8” NPT to reduce the flow to the water heater. I also have an in-line shutoff valve to further reduce and cut off flow. I have experimented with this while the engine is running and there is basically no difference in coolant temp. When I originally installed the water heater I had run the heater hoses in series as per a Westerbeke service bulletin. When converting to parallel, as it should be, I discovered a 1/4” nut had somehow fallen into the return line. This would have been severely restricting the coolant flow back to the engine. I was certain this was the cause of my overheating... I’m wondering if the fresh water pump could have been damaged by this? I was under the impression that they either work or don’t. The engine was overheating before the water heater was installed but who knows how many issues there were/are.
I have replaced all the other hose barb fittings with bronze Groco full flow fittings.

I discovered recently that in the parts manual the oil cooler is shown with a petcock drain and mine has a zinc instead. I removed the oil cooler last week to check it and also checked to see if the zinc may be causing a flow restriction. It didn’t look like it would but maybe I’ll try replacing it with a plug, at least temporarily. Does the oil cooler need a zinc? There’s one in the HE which I change regularly. The one in the oil cooler never seems to be depleted when I check it.

Apologies for the disjointed reply. I’m trying to write this on my phone with limited internet service.

[Poche]

I would be curious how it performs without a thermostat.

[jimbunyard]

At some point you're going to have to stop chasing your tail. All indications point to the exhaust being undersized and the prop being oversized.

As before, you may get lucky and one or the other might solve the problem, or it might take both.

A quick check shows a minimum of about 4-450.00 for hose and muffler whether 2 or 2 1/4 ID. Depending on where you're at, you might get a small prop repitched for about half that.

Since you know the exhaust is undersized, and you can change it without hauling or diving the boat, and even though the cost might be a bit higher than repitching, I'd do that first, because it needs to be done anyway.

Then you can repitch, if necessary (I'm betting it will be), secure in the knowledge that everything else is to spec.

[Wainui]

I had an overheating problem on my 4108 so I replaced the HE with a larger unit. It made a 15 degree difference In temp.
I still have the unit for sail as I have replaced the engine with a Beta 50.

[Cheechako]

Originally Posted by Dylancs

This is my third attempt at replying with limited internet.

The temperature increases linearly with rpm increase. The highest I’ve let it go was 210F at 3000rpm but it was still increasing. It always cools back down to 180F by about 1700rpm. The thermostat was one of the first things I replaced. It opens at 180F as it should.

When I bought the boat and saw the exhaust size, I was surprised. On my previous boat, I converted it from an Atomic 4 to a Yanmar 2GMF. I installed a 1.5” exhaust as per the manual. The Westerbeke is twice the size. The 1.5” section after the muffler is about 8’. My math tells me increasing to 2” is an 80% increase in volume. Maybe when the engine was new and running optimally the smaller exhaust size was sufficient. I haven’t check the raw water flow but I will attempt this when I’m back from my trip.

The Westerbeke W40 manual I have shows the max rpm is 3000. At 1800rpm I can do about 5.5kts. Theoretical hull speed is just under 7kts. I wouldn’t be surprised if the prop is over pitched. The PO said there was a feathering prop on it when he bought it but he didn’t like the noise it made so he replaced it.

Regarding the brass fittings, the hose coming from the head and returning to the HE are for the water heater. I intentionally reduced the 1/2” npt fitting to 1/8” NPT to reduce the flow to the water heater. I also have an in-line shutoff valve to further reduce and cut off flow. I have experimented with this while the engine is running and there is basically no difference in coolant temp. When I originally installed the water heater I had run the heater hoses in series as per a Westerbeke service bulletin. When converting to parallel, as it should be, I discovered a 1/4” nut had somehow fallen into the return line. This would have been severely restricting the coolant flow back to the engine. I was certain this was the cause of my overheating... I’m wondering if the fresh water pump could have been damaged by this? I was under the impression that they either work or don’t. The engine was overheating before the water heater was installed but who knows how many issues there were/are.
I have replaced all the other hose barb fittings with bronze Groco full flow fittings.

I discovered recently that in the parts manual the oil cooler is shown with a petcock drain and mine has a zinc instead. I removed the oil cooler last week to check it and also checked to see if the zinc may be causing a flow restriction. It didn’t look like it would but maybe I’ll try replacing it with a plug, at least temporarily. Does the oil cooler need a zinc? There’s one in the HE which I change regularly. The one in the oil cooler never seems to be depleted when I check it.

Apologies for the disjointed reply. I’m trying to write this on my phone with limited internet service.

I think my 4-108 had 2.5" diameter exhaust.
A 31 ft boat I built back in the 80's had a Volvo MD17 in it. It did exactly what yours is doing, overheated above a certain rpm. It was propped correctly too. In the end we decided it was not a enough engine for the boat, but it could have heat exchanger size as later in life I've seen threads about the same thing with that Volvo engine.