Impellor

[pabraam]

Removed the original Johnson (not Yanmar!) impeller from my 3JH4E Yanmar engine. However lubrification was not included with the new Johnson impeller, so my question is what do I use as lube.

Also, Yanmar states in its Operation Manual that impellers should be replaced every 1000 hrs. But on the forum I read that it is advisable to do this every year. That's quite a difference, so what's wisdom...?

(Difference between knowledge and wisdom:
knowledge is that you know that a tomato is a fruit, wisdom is that you don't put tomatoes in in a fruitsalad!)

Also, is it advisable to remove the impellor during winterstorage or during long times not using the boat and thereby taking the strain of the otherwise bended (or is it bent) rubber....? A bit like jacking up your car during longtime storage.

Peter A. Braam
o/b sv l'Entropist
Marina Muiderzand, the Netherlands

 

[anchorclanker]

Lots of thoughts. I have seen impellers over 5 years old that still looked fine. Being flexed in the housing doesnt seem to have much effect on them. They dont need lube, water is the lubricant. And any lube you did use would be washed away within moments. If you used something harmful it could attack the material. Its not rubber. It may have some in it but its likely neoprene or similar, and some have fabric inside.

1000 hours may be fine if the hours were put on rapidly, but time is a factor as well. Maybe more so. It certainly wont hurt to replace it once a year, or every other, when they get to a certain point they can die quite rapidly. Having it out to replace the impeller also allows you to service the other parts of the motor.

The chemical composition of the local water, if your running through sand or mud, or if you accidentally pull the motor up out of the water while its running all have negative damaging effects and a manufacture would term that abuse. Sand/mud can wreck an impeller in short order, minutes even, as can running it dry out of the water. Poor water will be slower to act but can also attack not only the impeller but all rubber parts. If its in a poor water environment dont leave it down in the water and rinse it after use if possible.

 

[kloudie1]

Talking diesel iinboard with sea water pump.. Lots of people change the impeller every season. I change mine every 2 years,, and we sail all year long here.. Much past 2 years is probably not wise, but many people do that as well.. My advice is to have a new impeller and case gasket on board .. inspect before launching ... replace if you see cracks at the base of the blades where they join the hub. It helps initial sealing and priming to lightly lubricate with silicone when the new impeller is installed .. 100 hour replacement is kinda normal for occasionally used boats .. My manual for the 3 GMF Yanmar says 1000 hours as well but I feel that is too long an interval..

 

[Jerry Clark H356 SV Persi]

I change my impeller on a 3GM30F at 150 hours or seasonally whichever is first. I sometimes have a broken blade even at that interval. I put a small amount of white lithium grease on the metal inside and on the blades prior to insertion. This makes it easy to go on and if a blade is going the wrong direction, then it will spin it to the right direction with little friction or wear on the blades.

 

[sailaway78]

Impeller

I change mine at intervals of no more than two years, and usually yearly. Like Claude I sail year round. I do use a light film of oil when I install a new one. IMHO it helps in the first couple of minutes while it is dry. Seems like it primes a little quicker with some lubrication. Always keep a spare on board. I have had one fail with less than 10 hours on it.

 

[John T1594]

Impeller lube

The last time I bought a new OEM impeller for my Yanmar 3GM30F, it came with a little tube of glycerine lubricant: labeled as CAS 56-81-5 lubricant for vanes Part # 01-46068-02.
BTW I change my impeller every other year.

 

[Steve Dion]

Re: Impeller

The impeller on the JH motor is different from the GM engines. They are gear driven (not belt driven) and are supposed to last much longer.

I just changed mine out this year which I assume was the original (1994 but very low engine hours). I was told that these impellers last much longer than the GM ones.

When I replaced mine I used some Teflon grease (Super Lube) to help with the installation. There is only about 1/2" of clearance between the starter and the impeller housing so some lube is very helpful. I also used a wire tie to reduce the diameter of the impeller.

I am not sure about the H38 but if it is like the 376 it may be worth adding an access door in the head area to make accessing the impeller much easier.

There is also a new tool that you can purchase to assist in the removal of the impeller. It MUST be a Yanmar impeller if you use the new tool. It allows the tool to be screwed into the impeller to assist with the extraction.

If the manual states 1,000 hours I would not get too excited about doing it every year or two.