Overheating engine. Not sure how to proceed.

[skipperpete]

Where is the pump for coolant circulation.... is it another jabsco or an electric pump?

[Jim Cate]

Well done, Matt. I take back some of those things I've said about you (not really).

Jim

[GILow]

In order of posts...

Wottie, you and I think the same way. Great minds think alike... or fools never differ... you decide. But yes, did the whole bucket thing and the raw water flow rate up to and including the heat exchanger was truely excellent. The coolant tank cap was some seriously odd thing without a pressure diaphragm so no idea of its pressure rating, if any. At this stage I am reluctant to mess with anything else because I actually think (hope) that the cooling is actually working fine and that it is all, quite literally, a false alarm brought about by an incorrectly set digital thermometer.

Skipperpete, the coolant circulating pump is rather awkwardly tucked away under the heat exchanger so I cannot be sure about it, but it appears to be an original integrated part of the engine, such as you’d see in any conventional car or truck engine. Again, I didn’t look too hard because I am optimistic that all is fine.

Jim, I expected no less. (And it was only an hour or two off the job here on the boat, and I needed a break.)

Matt

[fish53]

Originally Posted by GILow

Hi all.

I’ve just returned from visiting Juggles and partner on their boat.

I thought I’d put a few minds at ease by saying the boat is a LOT better in real life than the photos suggest. I think Juggles is the reverse of those photographers real-estate agents use to make houses look great when they are really a hole in the ground.

This is a very very sweet little Roberts which will give many years of happy sailing and service.

The cooling problem may well not be a problem at all.

It turns out that the previous owner has fitted a digital water temperature gauge and set the alarm to 86.5 degrees.

Now given this is a fresh water cooled engine (yes, it is a little hard to tell because it has an odd but pretty functional looking home made heat exchanger), I would say 86.5 is about exactly right for a fully open thermostat and no cause for an alarm.

So Juggles is going to run the engine up in gear in the pen tomorrow, this time with the alarm silenced, and see where the temperature stabilises.

I’ve never had a Lister engine, but I’ve suggested I would be happy with anything up to about 92 degrees, and even 95 at a pinch. But I would like to hear from anyone who knows these engines and can tell us what temperature they should run at.

I went through the basic checks of the cooling system. Raw water flow through the strainer and heat exchanger is excellent, really very, very good, but getting to the mixing elbow was not something I was willing to try unless there is a proven overheating problem.

Frustratingly, the exhaust outlet is right on the waterline so it’s very hard to gauge how much water is coming out. Aside from wedging a bit of flexible pipe in the outlet, I’d be keen for any suggestions on how to measure water flow in this scenario. (Mine is high enough to put a bucket under it, so I haven’t got any clever ideas yet.)

Matt

Edit: also, the pipe work is a lot better than it appears in the photos. The PO has used bilge pump hose in many sections, which, if my understanding is correct, is stronger against suction than normal hose but should otherwise be suitable. Again, I’d like to hear if there are problems with using such hoses in the cold side of the raw water circuit.

I've owned a number of those engines but in the air cooled iteration and the air cooled ones at least are quite tolerant of wide range of operating temperatures, which is why they used to be common in the West Texas oilfields. I'm not sure what you mean by "bilge hose" but anything other than wire reinforced marine water hose intended for use below the waterline I would be suspicious of. As I stated I believe it's a Lister STW which has quite a bit of information online, they're about 10hp per hole at 2600rpm depending on specific model. The rest seems to be kind of home engineered so I can't comment much on that.

[GILow]

Originally Posted by fish53

I've owned a number of those engines but in the air cooled iteration and the air cooled ones at least are quite tolerant of wide range of operating temperatures, which is why they used to be common in the West Texas oilfields. I'm not sure what you mean by "bilge hose" but anything other than wire reinforced marine water hose intended for use below the waterline I would be suspicious of. As I stated I believe it's a Lister STW which has quite a bit of information online, they're about 10hp per hole at 2600rpm depending on specific model. The rest seems to be kind of home engineered so I can't comment much on that.

That’s good to know about the temperature tolerance, thank you. Yes, it’s a 3 pot and was described as 35 HP so your numbers are consistent with that

The bilge hose I am talking about is sold for use with bilge pumps around here. It is a synthetic hose with a wire spiral encased in the plastic to stop the hose from kinking or collapsing. The wire itself is usually stainless but, in theory at least, it could be made from mild steel as it does not come into contact with the water, being fully encased in the hose material. There’s also a version where the spiral is just a ridge of thicker plastic, again just to give strength while keeping the hose flexible,

[Main ship]

It appears your impeller is improperly installed . Veins are in the wrong direction re instal lots of white grease bump over engine to se it. Is turning . Flush out it take and exhaust and see if water is moving . Stuff with a rag to aloe hose to pressurize . Pour in green or red food dye to see it come through

[Pcpete]

You are in for lots of hose. On the engine picture the hose going from the aluminum tank to the manifold is not cooling system hose. That braided stuff is for potable water. I’m also betting the corrugated pipe is for a hot water tank. Replace it with proper cooling hose.

[joe_bower]

All good points. Also, check the v-belt.

[t588143]

I had the same problem. By dislodging your boat while running the engine sand an silt has been digested in you raw water circuit and is most probably plugging the heat exchanger. Even. With a decent water flow part of the heat exchanger may be blinded causing a reduction of the cooling capacity. Cleaning everything out is the only remedy.

[Main ship]

All the hoses look Mickey Mouse on that engine I would get a professional to suggest locally but change all the hoses to proper .and do a engine room sweep for other potential future problems ... poor repair work is evident here ... know your boat saves a lot of worry

[ErnestV]

Originally Posted by Juggles

There seems to be a second seacock I wasn't made aware of. Partner wasn't sure if it was on or off. Handle fell off when trying to move itm retightened it.

This seacock seems to be closed, at least to my aged eyes.

Up through the floor to a unmovable handle. Seriously that circular wheel on top will not move. Pipe feels like it'd break before it'll turn.

For heavens sake you should replace this wheel valve with a proper ball valve. I bet it is brass as well - might sink your boat.

[GoinSumWare]

More than likely you sucked up a bunch of sand and simply need to empty your raw water strainer basket.

Originally Posted by Juggles

Hey there. This is my first yatch. Roberts 32 and I've got very little engine experience. Any engine. At all.
We were out, got stuck on a sand bank, dislodged eventually and motored home. Engine started overheating according to the gauge within two minutes. Unfortunately I don't know if it was doing this before the sand bank because I at that point found out my lovely partner had been motoring with instruments off! Should have checked on him down below. Great.

Anyway got her home had a look and my impeller wasnt broken but was squashed. Ordered a new one just in case and put the impeller back in right. Turned engine on. Overheated again. Checked the impeller and it's done it again. Repeated this two more times with the impeller looking like this each time.


More than likely you sucked up a bunch of sand and simply need to empty your raw water strainer baskets so that water flow is not impeded.

So looking at that I assume I have a swollen housing and either need to sand it down or buy a new pump?


Next problem. The damn thing is impossible to get off the hoses because you can't unscrew then from the pump end due to space. Not sure how they were put on to begin with. Already unmounted the pump just need to take the hoses off.... preferably without cutting. Any help is welcome. Same hose on both sides. Black corrugated with a screw attachment that seems to say hanen on it. I have spare corrugated hose but not those attachments. Not even sure where to get them.


And finally. I've only just.noticed. there's a piece of hose that leads to nowhere on this thing! Is that right? The old owner of the boat is a....well I don't want to swear that much but suffice it to say he's a lying lemon selling crook who managed to piss of a whole sailing club. He'll get his. Anyway. Because of him I can't trust anything I see on this boat. The wirings shot. It's like he didn't know what stainless was. Or marine grade ply. Or engine maintenance. Or antifouling. Or anything really. I could go on but the cooling system is today's problem. If you look close. It's the clear hose that leads of the red hose that just...ends in mid air?


Here's a picture of the engine for completeness. It's a Lister hw3m. Not even a common easy engine to deal with.
[url=https://ibb.co/MS5d6ht][/url

[gravedigger7142]

I would also go round and squeeze or replace the hoses. Lots of salt and gunk builds up over time near the bends. Wont be hard to fix. I suspect it wasnt overheating dangerously before grounding as it probably may have siezed. Aslo check for blocked seacock, then maybe fit a stainer

[Jimmyhenry]

We had an overheating engine just as we entered the Amedeo Passage into the southern lagoon of New Caledonia. Not a nice place to lose an engine. Turned out to be the spline on the impeller itself which had become detached from the rubber part of the impeller. Engine was an 85hp Yanmar and the impeller was the correct yanmar part.

Pete

[GILow]

Guys, read my followup posts. The cooling system is most likely ok, the impeller vanes are exactly as they should be and the raw water flow was better on this 35 HP than my own 96 HP engine.