Yanmar 3gm30f water pump

[Jacquesau]

Hi

Has anyone ever tried to use an electric water pump to cool the engine instead of the Johnson pulley driven pump?

So before turning the engine over switching the pump on and letting it run constant water. I have read up and seen that there are quite a few issues with the water pump">raw water pump as is.

[RaymondR]

I did it using a single pole, double throw relay to keep from flooding the engine.

I wired the power supply for the pump from the ignition switch through the normally closed contacts on the relay. Then wired the actuator coil from the oil pressure warning light circuit in parallel with the warning light.

When you switch the ignition on two things happen: first the pump tries to run because it is wired through the normally closed contacts of the relay. But, because there is no oil pressure the actuator coil is powered and pulls the relay in switching off the pump. In practice both things happen together.

When the engine starts the oil pressure switch opens cutting the current to both the warning light and the relay actuator coil and the relay opens thereby closing the normally closed contacts and the pump then starts.

When you kill the engine and the oil pressure drops and switches the warning light on the relay opens the normally closed contacts so that the pump will not run and back flood the engine. When you turn the ignition off there is no power to the pump.

I installed that system in 2011 and it is still working well today. It's a bit unorthodox and has baffled a couple of mechanics because we normally use relays to power things by closing the normally open contacts and not open them.

[Jacquesau]

Thanks for that will have a look into it.

[ggray]

What size water pump did you install?

Originally Posted by RaymondR

I did it using a single pole, double throw relay to keep from flooding the engine.
<snip>

[RaymondR]

Originally Posted by ggray

What size water pump did you install?

I believe it was, or was similar to, the Jabsco Water Puppy 2000 impeller pump which is rated to an output of up to 32 LPM but the actual output depends upon the back pressure the pump is working against.

There were two instances of my using an electrical impeller pump on my engines.

My first use was on a Yanmar 3GM30 raw water cooled engine where I used it a number of times because of failure of the belt driven pump. It more than adequately cooled the engine on the number of occasions I was obliged to use it. However as it was a contingency measure I did not bother with the electrical system I described in the former post.

The electrical system I described was used on the same pump after I re-engined the boat with a 50 hp Kubuto. It was used to provide cooling water to the exhaust system. The engine cooling was done via a keel cooling system.

[Simi 60]

How do you adjust for different rpm needing different water flow?

Electric pump on fixed rpm genset is one thing and I have done it, but on a primary?

[RaymondR]

Originally Posted by Simi 60

How do you adjust for different rpm needing different water flow?

Electric pump on fixed rpm genset is one thing and I have done it, but on a primary?

You don't have to adjust it, whether it's directly raw water cooled ie. sea water circulates through the engine or indirectly ie. sea water cools fresh water circulating through a heat exchanger, just make sure that the electric pump will pump sufficient raw water to cool the engine at maximum load.

Maintaining the engine temperature correctly is the job of the thermostat which will open and close to keep the engines cooling fluid outlet at the correct temperature no matter whether the engine is raw or fresh water cooled.

[Simi 60]

I would think your engine would run a bit to cold if puttering along at 1000rpm with water flow you would usually get at 3000rpm.

[johnjuliano]

The only problem I see is that the 3gm30f is a completely mechanical engine, meaning that once it is running it needs no electrical power of any sort. The batteries can die, the alternator can die – if the charging system is flakey, once the engine is running, it will run until it runs out of fuel.

By adding an electric water pump, you must have a working electrical supply of some sort to run the water pump.

[stewy]

I wouldn't complicate matters. I just bought a spare water pump for the same engine from Devco Pump Company in Clearwater from Dorian for $242.77 + tax. This is the Johnson pump with Yanmar number YM 128397-42500.

[roverhi]

Installing an electric pump for the belt driven pump on the GM Series Yanmar's seems to be a lot of work for small reward and a big negative. Pumps are easily removed to service, if necessary, have been quite dependable on both my 2 GM and 3 GM engines. Expecting an electric pump to be more reliable than a belt driven pump flies in my experience.

[a64pilot]

Originally Posted by Simi 60

I would think your engine would run a bit to cold if puttering along at 1000rpm with water flow you would usually get at 3000rpm.

Due to the thermostat, I don’t believe it would. The danger I believe is excess water flow at too low of an RPM may be more than the engine could expel. Think dead idle.
Get it low enough for low RPM and it may not be enough for high load / high RPM.
After going to an electric pump on my generator and having such success with it I considered doing the same for the big motor. I believe you could actuate a ball valve with the throttle cable to modulate water flow close enough, but in truth my factory impeller pump has so far been so trouble free, there just isn’t the need.

[RaymondR]

On my 3GM30 the raw water impeller pump hung under the engine and the drive pulley was the innermost of three, the other two driving 2 alternators. The tiny V belt on the water pump was prone to an occasional failure and with removing and replacing V belts and adjusting tensions etc. it was at least an hours work to change a belt.

In contrast the installation of the electric pump was a matter of swapping two hoses and clipping on a couple of alligator clips or about five minutes.

On the Kubuto installation the pump only supplied cooling water to the exhaust system. I originally installed it because it was too large a project to make it an engine driven, belt drive system and I was time constrained. However after doing about an 8,000 nm coastal cruise around Australia and back I decided it had proven sufficiently reliable to become a permanent fixture.

I had gone mad on the redundancy thing on the Kubuto and it had two complete electrical systems including two starter motors.

The second impeller pump was not completely installed it needing a couple of hose swaps to complete. The first, fully installed electric pump proved sufficiently reliable that it is still in use today and I cannot recall ever replacing the nitrile impeller in the eight years I used the boat after the Kubuto installation.

Thinking back on it I am inclined to the opinion that the electric driven pump on the Kubuto has proven to be more reliable than the belt driven pump on the Yanmar as I was obliged to use the electric driven contingency pump two or three times on the yanmar but never the second pump on the Kubuto.

Seems a bit contra intuitive but there it is.

[Howler]

Having run a3GM30F engine for 25 years with no raw water pump is problems sues, I subjectively second the view that the mechanical system as designed is optimal and relies on no alternative power sources. Of course, you need to check / replace your impeller often and carry a spare. As for belts, they don't require replacement often, so an hour's work seems reasonable.

[RaymondR]

Originally Posted by Jacquesau

Hi

Has anyone ever tried to use an electric water pump to cool the engine instead of the Johnson pulley driven pump?

So before turning the engine over switching the pump on and letting it run constant water. I have read up and seen that there are quite a few issues with the raw water pump as is.

There are two questions in the originating post: has anyone done the electric and, how do you manage the problems related to electrification.

Yep, done the electrification of a Yanmar 3GM series and it works.

Using a relay and the accessory terminal on the ignition switch you can manage the related problems.

Whether one should do it or not depends upon ones perceptions and priorities.