Overheated

[ArtJ]

Seabee,

If you haven't yet, you should read these recent threads regarding replacement impellers:

http://www.moyermarine.com/forums/showthread.php?t=4038&highlight=short+impeller

and

http://www.moyermarine.com/forums/showthread.php?t=4222&highlight=short+impeller

The attached picture has the labels reversed but it clearly shows the problem.

and Baltimore, what ever became of your related issue?

What is the current status of the impeller / chamber issue?

Has Moyer Marine resolved the issue?

[ndutton]

What is the current status of the impeller / chamber issue?

Has Moyer Marine resolved the issue?

I think the first thread referenced earlier, specifically Don's post on 6-7-2010, establishes the Moyer position on the issue.

[ArtJ]

I wonder if the practice of coating the pump chamber with a little lithium grease during impeller replacements helps reduce some wear?

[Seabee Chief]

Grease

Art,
One of guys at the dock said to use vaseline gelly but I would go with the lithium grease. After all if you have a grease cup, it keeps the bearing in good shape. I do not think it will harm the impeller.

Chief

[hanleyclifford]

What would be the advantage of lithium grease over petroleum jelly or other grease without lithium? Is not lithium a metal or earth salt?

[Administrator]

I have seen impeller replacement "kits" which contained a small squeeze tube of lubricant, which was intended to facilitate inserting the new impeller into the pump. Not sure exactly what the "lubricant" was, but I suspect it would last about as long on the impeller as that famous barnacle barrier for props, zinc oxide.

OTOH, no one ever reported diaper rash on their prop after using the stuff.

Bill

[Jesse Delanoy]

The Moyer MMI pump rebuild kits come with a small amount of grease in a plastic pack. Instructions didn't (I think) say what it was for.

Jesse Delanoy

[smosher]

Besides the pump chamber, I also grease the shaft.

[Baltimore Sailor]

BS

Mine also will not get up to full throttle. I usually run at 1800 RPM with 150 deg and get around 6 knots depending on the current.
This may be a good question to take a poll on.

Chief

Mine will get up to full throttle (2000 rpm for me); it'll just overheat if I run it there. I need to keep it at 1500 to keep the temp at a reasonable figure.

[Seabee Chief]

Roger that, my magic number is around 1800 RPM. After that the temp will be climbing.

[hanleyclifford]

Interesting that both members here (preceding two posts) have the issue of rpm being limited by cooling ability. Most A4's rpm are limited by prop selection and hull configuration. Maybe we need to talk about cooling system design?

[Seabee Chief]

Update

Guys,

After changing the thermostat this weekend she is still running hot. At the dock at 1200 RPM she was running 190-200 deg. I tested the thermostat prior to installation and it was working properly. I also tested the old thermostat and it was opening on the high side of 190. I am getting water out of the exhaust so I know water is flowing. I believe I may have gotten some crud broken loose in the engine and want to perform a good flush on the engine with muradic acid. I am tired of loosing weekends and may just purchase the MM502 water pump to replace the original one that I currently have on the engine now. The water pump may just be tired and I know I will get a good flush if I had a strong pump on the engine. Any other ideas?

Chief

[ArtJ]

I would get the moyer flushing kit and procedure. It is a bargain. I think
around seventy bucks.

It does a super job of cleaning out your cooling system systematically.

Regards

Art

[Seabee Chief]

Thanks Art, I will look into the Flushing Kit.

[rigspelt]

Here's my experience with the MMI flushing kit. I probably could have done a longer vinegar soak, although the engine is cooling efficiently anyway so the passages must be pretty clean. http://www.moyermarine.com/forums/showthread.php?t=2959