An electric pump instead of the Jabsco impeller??

[Cheechako]

I have considered this and chose not to. IME electric pumps are far more trouble and a far higher failure rate than mechanical pumps.
Why not just set up your Perkins pump with proper strainers and etc.? Done right and operated right it will last a very long time without repair.

[Jolly Roger]

It’s not off-topic at all Idaho. In fact, that was the reason I started this thread in the first place. If you’ve had a complete shredding of a 12-leg impeller, there is only one remedy IMHO, and that’s to strip and clean all the raw water pipes, even back to the exhaust elbow.
Start at the seawater inlet and take all the pipes off and clean them. When you get to the raw-water pump, follow the pipework through, all the way to the exhaust.
This is what I’ve done on my old Perkins 4.236, which is a big heavy engine, and it’s taken me a month to strip it and clean out all the pipes, and both heat exchangers. I’m just starting to rebuild and document and photograph it all, for an article I’m writing for one of the boating magazines, so it might take another month to finish the engine.
Here are a couple of shots along the way.
I agree with Cheechaco. I will keep the original cooling system and only add one of the flow meters/alarms just for safety.

[Simi 60]

Originally Posted by Cheechako

I have considered this and chose not to. IME electric pumps are far more trouble and a far higher failure rate than mechanical pumps.
.

Yeah, can't say I agree

Our mechanical pump on the Genset failed a couple of times a year - impeller
Blood and swearing was involved to repair.

Electric pump has been in 5 years, zero issues.
Same pump I have used in another application has many more years again on it.

Iwaki MD 30 clone on eBay for $140.

[Uncle Bob]

Originally Posted by Jolly Roger

It’s not off-topic at all Idaho. In fact, that was the reason I started this thread in the first place. If you’ve had a complete shredding of a 12-leg impeller, there is only one remedy IMHO, and that’s to strip and clean all the raw water pipes, even back to the exhaust elbow.
Start at the seawater inlet and take all the pipes off and clean them. When you get to the raw-water pump, follow the pipework through, all the way to the exhaust.
This is what I’ve done on my old Perkins 4.236, which is a big heavy engine, and it’s taken me a month to strip it and clean out all the pipes, and both heat exchangers. I’m just starting to rebuild and document and photograph it all, for an article I’m writing for one of the boating magazines, so it might take another month to finish the engine.
Here are a couple of shots along the way.
I agree with Cheechaco. I will keep the original cooling system and only add one of the flow meters/alarms just for safety.

Hi, the addition of an inline strainer directly after the water pump">raw water pump outlet will catch any errant impeller pieces before they can venture too far. You have one prior to the pump so something similar directly after the pump would work well.

[s/v Jedi]

Originally Posted by Uncle Bob

Hi, the addition of an inline strainer directly after the raw water pump outlet will catch any errant impeller pieces before they can venture too far. You have one prior to the pump so something similar directly after the pump would work well.

Here’s how to do that. The inner part I made from thin wall PVC pipe. The largest opening is smaller than the channels in the heat exchanger.

If you see impeller parts, you replace the impeller

[RaymondR]

If you spend a lot of time motoring in places with lots of weed and other clogging materials the ultimate solution is keel cooling.

[Idaho]

Thank you, J. Roger.

[Jolly Roger]

Another good idea from Uncle Bob and SV Jedi. Believe me, you don't want to have to completely strip an engine if the impeller disintegrates. If you are operating in the ICW or any other shallow sounds it's much better to incorporate safeguards.
We all live and learn.

[andrzej0nl1ne]

What is the water pressure on the output side of the pump. As in what type of filter needs to be installed to trap the broken vanes?

[goboatingnow]

Originally Posted by s/v Jedi

Here’s how to do that. The inner part I made from thin wall PVC pipe. The largest opening is smaller than the channels in the heat exchanger.

If you see impeller parts, you replace the impeller

good idea maybe the little plastic jabsco plastic ones would work for my little MD2030

[s/v Jedi]

Originally Posted by goboatingnow

good idea maybe the little plastic jabsco plastic ones would work for my little MD2030

The ones I could get did restrict the flow. The stainless steel ones are okay but they catch too much. This only stops what would get stuck in the heat exchanger channels

[Jolly Roger]

Hi SV Jeda:
I’d like to install a filter like yours after the impeller, for the reasons you explain, but can I ask?
Did you make the inside of your secondary filter yourself? What was the size of the bowl, why can a standard steel gauze collect “too much”? I would have thought this would be a good thing, to collect even smaller pieces of muck, but is it because this would restrict the flow, even when clean?
I propose to fit a large filter with a 6” deep bowl.
The first item after the impeller pump on my Perkins is a solid I” inch pipe to the oil heat exchanger, then to the main water heat exchanger, and into the block.
I really want to prevent a repeat of what I’m going through now, dismantling, cleaning, and rebuilding for the past month, and still at it…

[hpeer]

Following with interest.

When we bought our boat it had 672 hours on the motor. I replaced the impeller and it was fine. I would periodically remove and replace the impeller.


At 2,000 hrs I had the heat exchanger removed and serviced. The mech found a complete set of vanes in the heat exchanger, apparently right at the begining. So this failure happened before we bought the boat.

I noticed no problem with the engine before this discovery and mi improvement after. Perhaps it is something with the way the 4-JH4 exchanger is designed? Don’t know.

[s/v Jedi]

Originally Posted by Jolly Roger

Hi SV Jeda:
I’d like to install a filter like yours after the impeller, for the reasons you explain, but can I ask?
Did you make the inside of your secondary filter yourself? What was the size of the bowl, why can a standard steel gauze collect “too much”? I would have thought this would be a good thing, to collect even smaller pieces of muck, but is it because this would restrict the flow, even when clean?
I propose to fit a large filter with a 6” deep bowl.
The first item after the impeller pump on my Perkins is a solid I” inch pipe to the oil heat exchanger, then to the main water heat exchanger, and into the block.
I really want to prevent a repeat of what I’m going through now, dismantling, cleaning, and rebuilding for the past month, and still at it…

A good raw water system starts with a thru-hull fitting and seacock, immediately followed by a large capacity sea strainer. This is where you filter the water. The strainer put in after the impeller pump is only to catch impeller parts that would otherwise get stuck in the heat exchanger. It’s filter openings do not need to be smaller than the smallest openings in the heat exchanger.

When I did use the plastic insert that comes with the small strainers, water flow through the generator (it’s on my generator) was reduced. With the stainless steel version it was okay, so I used that. What you end up with is having to clean it because small particles that pass the big sea strainer get caught, instead of just the larger impeller pieces. This makes it an annoyance leading to either neglect or disuse.

Also, you will find impeller pieces in the outlet fitting of the impeller pump. This is the #1 location where they end up and can block flow completely. I’ve seen people take their heat exchanger apart, finding nothing because they skipped taking the hose off the pump outlet to check that first.

[Jolly Roger]

My oil cooler/exchanger was almost completely blocked on the inlet side with the larger broken vanes and muck. This might eventually have overheated the transmission, then I would really be in trouble.
This episode has been a wake-up call for me, and since our new sailing ground is the fairly shallow Pamlico Sound, NC, I intend to build in both a secondary filter just after the pump, and also the flow alarm mentioned previously.
Jedi’s point about access and consequential neglect is very true, and I have to confess, it’s one of the reasons I’m in this pickle now.