Raw water impeller "end plug"?

Just changed the raw water impeller on my Lehman 135. The old one was Jabsco and had a little flat rubber disc that sealed the shaft against the cover plate. The new one was Johnson Pump and fit perfectly, except that it didn't come with a similar disc, and the old one was slighly too big to fit. I could cram it in there, but with the lube, it would pop out.

I just reassembled without. I'm guessing it's not a necessary part since the new one came without? Right, wrong? Effects?

I've used impellors with and without the disc and it never made a difference.

Just wanted to throw in a good word for Globe impellers. We put 2012 hours and 7 years on the last one and when I pulled it yesterday it looked as good as new except for discoloration from the water around here. All vanes were intact and there were no worn spots on the ridges at the end of each vane. Put the used one back in the spares box for a backup.

I have a FL 120 and I have changed the original pump to the new Johnson Pumps replacement.

I learned that while Jabsco makes an impeller that they claim will fit the Johnson pump, the impeller is about 1mm longer than the Johnson impeller. That extra 1mm has caused the impeller to wear the brass cover plate excessively.

When placed on a table side by side, it is easy to see that the Jabsco impeller is taller than the Johnson.

My Johnson impellers don't have the rubber end plug either. I did reuse the Jabsco end plug, but I don't know if if is needed.

Keith said:

Just changed the raw water impeller on my Lehman 135. The old one was Jabsco and had a little flat rubber disc that sealed the shaft against the cover plate. The new one was Johnson Pump and fit perfectly, except that it didn't come with a similar disc, and the old one was slighly too big to fit. I could cram it in there, but with the lube, it would pop out.

I just reassembled without. I'm guessing it's not a necessary part since the new one came without? Right, wrong? Effects?

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Keith, I have often wondered the same thing and will watch this space with interest. On a related subject: I've spent many miserable hours and knuckles removing large impellers from dry splines. Copper never-seize on the splines is a really good investment. Jabsco's impeller pullers are a good investment too. The Use of screwdrivers as levers to extract a reluctant impeller is a really bad idea.

Well, put about 50 hours on with no ill effects so far. Probably won't have a full report until I change it next. I use either silicone plumber's grease or Tef-Gel on the spline, and do use the Jabsco puller. Also have the Speed-Seal cover which makes things much easier!

Compressing the vanes on new impellers so that they will slide into the pump can be a struggle. I came up with a plastic version of a piston ring compressor - worked like a charm and cheap too! The plastic strip/sleeve was cut from the side of a gallon ice cream container - sort of Tupperware material. The hose clamp will squeeze the sleeve sufficiently that it (the sleeve) will slide into the pump barrel by 1/2" or so. Push the impeller out and withdraw the sleeve. Plenty of silicone grease on the impeller and sleeve, plus copper Never-Seize (or other lube of choice) on the bronze splines.

Keith, as you know I put many thousands of hours on CCRIDER, 6300 PLUS and used the rubber plugs if I had them, no effect either way.
Like you I use a grease on the splines, NEVER SEIZE and compress with a plastic wire tie, Use needle nose Vise Grips to pull the impeller.

Shoalwaters said:

Compressing the vanes on new impellers so that they will slide into the pump can be a struggle. I came up with a plastic version of a piston ring compressor - worked like a charm and cheap too! The plastic strip/sleeve was cut from the side of a gallon ice cream container - sort of Tupperware material. The hose clamp will squeeze the sleeve sufficiently that it (the sleeve) will slide into the pump barrel by 1/2" or so. Push the impeller out and withdraw the sleeve. Plenty of silicone grease on the impeller and sleeve, plus copper Never-Seize (or other lube of choice) on the bronze splines.

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MIKE! you are a genius. Last time we must have used about 20 zipties trying to get that $%&* thing installed. they kept popping off at the worst possible time.

I used tie wraps a couple off times, but generally the impeller goes right in with no compressor aid. A little "pam" spray and have someone jog the engine while I put pressure on the impeller with my palm usually does the trick.

jleonard said:

I used tie wraps a couple off times, but generally the impeller goes right in with no compressor aid. A little "pam" spray and have someone jog the engine while I put pressure on the impeller with my palm usually does the trick.

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I agree...the Lehman impeller is pretty easy in comparison to many size water pumps.....as long as the impeller you get is as soft as the last couple I played with.

I found JUST a hose clamp was enough to curl the ends of the impeller down enough to make it a one handed job. Once 1/2 inch or so of the impeller was in...it was easy enough to push the impeller right through the hose clamp and into the housing.

I use dish soap and pour a little water into the intake hose prior to start..

psneeld said:

I agree...the Lehman impeller is pretty easy

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I agree, too. Our engines had the stock Lehman drive coupler/Jabsco pump setup when we bought it and we ran them that way for a number of years. The old impeller was always easy to remove and the new one twisted right on in with aid of some Lemon Joy dish soap.

But it's just a matter of time before the Lehman drive coupler fails and when it does it cannot be repaired effectively and new ones no longer exist. Even Bob Smith who designed it told me that while it seemed the best design at the time it's not, and it 's the only part on an FL120 to have a factory recall when the engines were new. Unfortunately the recall didn't really improve things much so the drive coupler is still a failure waiting to happen.

A pump/drive removal for another reason revealed that our port drive coupler was in the process of failing so we took our shop's (and Bob Smith's) advice and replaced the whole deal on both engines with new one-piece, 1" Johnson pumps.

And I was pleased to learn that the Johnson impellers come out and go in every bit as easily as the impellers in the old Jabsco pumps. We do have an impeller puller but so far we've never had to use it. The Lemon Joy has been the only "tool" we've needed to date.