Overheated

[Seabee Chief]

After changing our head gasket a few months ago, everything was running great! Yesterday the temp was normal until we were coming into the channel and I saw the temp gauge was buried at 225. I couldn't shut her off in the channel so I made the commitment to putt up to the fuel dock. (the first dock in the marina) It was a short 200 yards up the channel. As soon as I cut the corner I throttled down and she stalled about 50 yards from the dock. I was able to coast in and the dock hands were able to stop me with spring lines. Close call! I got a tug over to my slip. It could have been worst.
I didn't have time last night, so this weekend I plan to start working the problem by the numbers. First thing will be to check the strainer for blockages. Then check the impeller. I have never checked either since obtaining the boat last fall. If both check out OK, what else would cause the sudden rise in temp? When we changed the gasket we flushed out the engine really good. Is it time for the fresh water change over? Would it have mattered?

Chief

[Administrator]

You could have sucked some debris (plastic bag, etc.) up against the thru-hull intake which would have shut down the flow of water. This may have fallen harmlessly away when you shut the engine down, or not.

Key question: Were you discharging cooling water out the transom when you overheated? That will tell you a lot.

Bill

[ndutton]

If you have a blockage or failure in the raw water circuit, FWC won't make a difference. Were you shipping water out the exhaust? That would be a clear indicator right there. On my C-30 I can hear the water splooshing out the transom all the time, I particularly listen for it. When it doesn't sploosh (only once since I've owned her) the exhaust echos.

edit: I see Bill was typing at the same time as me.

[Seabee Chief]

Thanks for the quick responses.
There was no water coming out of the exhaust.
I think that's what made me look at the temp gauge in the channel.

[sastanley]

Fire her up at the dock and see if she splooshes water now...if so, I'd agree with Bill..a momentary blockage...if not, then we have a failure somewhere.

[Seabee Chief]

Will do. I will let you know how I make out this weekend. One thing for sure, I am going to install that MM alarm kit I purchased a few months ago.
One thing with the alarm kit, currently my blower only works when the key is on. If I hook up the alarm kit as is, the alarm will sound the whole time I am purging the engine compartmant. Shouldn't I re-wire the blower right from the battery? Will I have any problems doing this?
Chief :confused:

[roadnsky]

Will do. I will let you know how I make out this weekend. One thing for sure, I am going to install that MM alarm kit I purchased a few months ago.
One thing with the alarm kit, currently my blower only works when the key is on. If I hook up the alarm kit as is, the alarm will sound the whole time I am purging the engine compartmant. Shouldn't I re-wire the blower right from the battery? Will I have any problems doing this?
Chief :confused:

Chief-
No problem hooking it up that way.
Many boats (including mine) are wired with the blower on it's own circuit switch.

[sastanley]

Chief,

Re: blower wiring. Yes..

You simply need to move the +12v that goes to the blower switch over on the key, which is where I suspect it is currently wired. It needs to move to the terminal on the key that is hot all the time, instead of the "On" position. I just wired up a voltmeter in the cockpit that I only wanted to work with the key on & I noticed how the bilge blower was wired...I would NOT want the blower wired to the "on" position..you are burning up your coil & points/ ignition when running the blower before starting. :eek:

Do you have a separate on/off switch for the blower? Mine is a pull/push switch right next to the key in the instrument panel.

[Seabee Chief]

Yes I do have a separate toggle switch next to the key for the blower. I also have another small bank of swiches in the cabin that allows power to the cockpit. I believe when these are shut off, it will also cut power to the blower, so no one will accidently turn it on.
I will have to check it out this weekend and do some tests.
Chief

[Seabee Chief]

This weekend we inspected the sea strainer and it was clear.
Then I pulled the back plate off the water pump and inspected the impeller.
It also looked great. I turned it over while my wife watched the impeller turn.
It seemed to be working properly. I replaced the back plate and started the engine. Water started coming out of the exhaust after a short period of time and the temp began to rise. My thermostat should open at 140. After the temp was up to 190, I shut it down. I now believe this is my problem and have ordered a replacement from MM. I'll let you know how we make out.

[ArtJ]

Before giving up on your current thermostat, try putting it into a jar of
vinegar for a day or two. Most thermostats respond favorably to this
treatment. Especially if you have one of the Bronze holley three spring
thermostats which Don Moyer raves about, you would want to save it.
you can test with hot water on your stove and see it opening and
closing after cleaning.

Regards

Art

[ndutton]

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?

[Baltimore Sailor]

My issue hasn't gone away, or been fixed. I'm just using my old impeller for the rest of this season, and plan on replacing the water pump over the winter.

Actually, I've been having overheating problems lately -- I can't run at full throttle without it moving up towards 200 F, so I keep it at 1500 rpm and she runs steady at about 190 or so. I think I've got a bunch of growth on the bottom, but I can't find anything flexible enough to run down my through hull to try to clean it out. I'll be getting her powerwashed soon, so hopefully that'll take care of it. I also plan on doing a power flush as well.

[Seabee Chief]

Art thanks for that suggestion.
When we changed the head gasket a few months ago, I did flush it out good and tested the thermostat. It was tarnished but tested fine. I will do the vinegar and test it again. If it works, I will keep it as a spare on board.

Neil,
Great threads, thanks.
Next season I plan on replacing the impeller and add the MM Back Plate to the pump.

Thanks again for the replies.

Chief

[Seabee Chief]

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.:rolleyes:

Chief

[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]

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.:rolleyes:

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]

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 :confused:

[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. :D

[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

[ArtJ]

Thanks Art, I will look into the Flushing Kit. :D

I suggest using the deluted muriatic acid per Moyers instruction sheet.
If you are going to this much trouble, you want to be sure to clean it
out thoroughly the first time.

Art

[Seabee Chief]

Well, we when down this weekend, started the engine and brought it up to op temp around 150-165 and started closing the by-pass. The temp was slowly rising so I completely closed the by-pass. She was still running hot @ 190-200 @ 1200 RPM. We must have clogged jackets in the engine. So I bought a MMI Flush Kit along with a new impeller, thermostat housing and gaskets. The old housing is badly detererated and may not be making contact with the top of the thermostat. I'm tired of loosing weekends on the dock. :mad:
Very frustrating, but we will get there.
This weekend I will start point to point and look at where the blockage may be. But it must be in the Block.

Chief

[hanleyclifford]

Have you inspected the water outlet fitting on the manifold for clear flow?

[rigspelt]

And the raw water entry to the exhaust dry stack? But you mentioned in your original post that you were going to check all the hose connections for a blockage.

[hanleyclifford]

Checking hose connections is not enough. The fittings must be removed and cleaned and a probe run into the casting. It is possible the manifold itself is blocked. I have cleaned some manifolds from engines that had been running that I couldn't believe would pass ANY water.

[Seabee Chief]

Guys,
Thanks for the feedback. I intent to do a full strip down of the hoses and fittings this weekend. Last weekend we were getting water out of the exhaust, but it was infrequent with the by-pass closed. Which leads me to believe not enough water is flowing through the engine. This problem really started rearing it's ugly head when the surface temp of our water got to about 70 degress. Yesterday I recieved the flushing kit, impeller, gasket, new hose and a new thermostat housing. Wow is that what the inside of the housing is suppose to look like! Ours is completely corroded and rounded off on the inside. I will be changing everything out and see if it will make a difference. Then I will perform the flush once I confirm good flow to the T-fitting. Another thing is that my by-pass is an old gate valve that may have a bad washer in it and is not completely closing flow. I will inspect it and may replace it with the small shut off included in the flush kit.
I'll keep you advised.

Chief

[roadnsky]

...Another thing is that my by-pass is an old gate valve that may have a bad washer in it and is not completely closing flow. I will inspect it and may replace it with the small shut off included in the flush kit.
I'll keep you advised.

Chief-
One more piece of unsolicited advice...
Gate Valves have no place on a boat. REPLACE it. (IMHO) :o

[sastanley]

Chief, what jerry said. Hopefully the boat itself doesn't have any left either, but that was standard practice in C-30's back in the day. If there are any left, they need to come out on the next haul out. dbschulz and I are talking about that offline now. It was a few days work..probably one weekend if you went at it full on. I suggest backing plates 5200'd to the hull & marelon seacocks & thru-hulls fittings

How'd the bypass for the engine get built with a gate valve?? :confused:

[Seabee Chief]

Jerry & Shawn,
Thanks for the advice. I believe this is the only ball valve on the boat. Ken from MMI said that some people did this years ago, so it proably is shot. All the thru-hull valves are ball valves and are in great shape. I will change out this by-pass with a ball valve this weekend.
Thanks again,
Chief :)

[Seabee Chief]

Guys here is an update to hopefully a resolved issue.
I purchased a new MMI bypass kit to replace the old ball valve bypass on the engine and replaced all the hoses. The old hoses were dry rotting.
Then I removed the thermostat and checked it in boiling water. (just purchased) Then I poured a couple cups of Muratic Acid into the head then re-assembled the housing less the thermostat. Started the engine and put the inlet hose into the gallon jug of Muratic Acid. Ran the engine until the jug was empty and shut off the engine. Waited 20 mins then started the engine.
WOW! We captured what came out of the exhaust in a bucket. You couldn't believe the rainbow of colored crud coming out of the exhaust. And I never saw so much water come out of the exhaust. During the whole time the bypass was closed so all the water went through the engine. After running the engine for 10-15 min more, I opened the bypass to bring the engine temp up. She ran cool as a cucumber!:D I used a laser temp gun to check the head temp. Cylinders #1 & #2 stayed around 100-120 deg and #3 & #4 were around 130-140 deg. It never got hotter. I figured when under load the engine might warm up more, then I can close the bypass if needed. The water temp coming in is around 62 deg. I didn't have time to take her out yesterday for a sea trial. I will do this next time I get down there. Thank you for all your advice and MMI for stocking these parts.
Just one question: Is there any problem with an engine running too cold?

Chief :confused:

[Administrator]

Did you use the muriatic acid straight, or did you dilute it with water beforehand?

Bill

[sastanley]

Chief,
Good news! To answer some of your questions:

Yes, running an engine too cold results in more internal deposits..like salt & stuff..you need the cooling water running thru the motor hot enough to keep deposits from forming.

I have a suggestion about the bypass...don't think of it as only open or closed. I have mine somewhere in the middle to keep an engine temp of 160-165. I think with it closed all the way, the engine simply runs too cold, but left open and the engine temp fluctuates quite a bit. If you adjust it while the engine is running you can see almost instant changes in the gauge reading.

I'll echo Bill's question..you should dilute the muratic acid, if I recall about 3:1 with water. Good thing you didn't leave it in for long! :eek:

[Seabee Chief]

Bill & Stan,
With the speed the engine was overheating, I knew I had serious blockages.
So I did use it straight out of the bottle, but only for this time.
I hope I did not cause too much internal damage. All I know is the exhaust would only spurt out a little water every 5 seconds and now it has a heavy spurt every 5 seconds with a smaller one between. Water is flowing like a brand new engine. I'll have to cross my fingers!
Now I know the jackets are clean and will maintain them with the recommended maintenance. I plan on doing the power flush this Spring.
During the diagnosis of the overheating problem, I started installing the MMI alarm kit and snapped of the nipple for the oil pressure sensor. It came out with an easy-out, but I do not want to touch any more fittings until next year
Got to get a few more sails in this year.
I wouldn't recommend anyone using the acid straight but this was an extreme case. This motor sat idle with no maintenance for 4-5 years.
Thanks again for all the advice, :)

Chief

[sastanley]

Chief, If you had the original oil pressure nipple, those are prone to failure. If you got it out clean (with the easy out :confused: ), now all you need is a proper tap to clean the threads for a new pipe nipple (brass!!) - I had to do this with my stbd aft block drain two years ago, as the nipple was epoxied to the block :rolleyes: There are lots of pics floating around here of that, I won't repeat them. Check out my "old boat, new owner thread.." :o

[Seabee Chief]

Thanks Shawn,
Will do.
Chief

[Administrator]

...dilute the muriatic acid, if I recall about 3:1 with water.

This is probably an unnecessary addition, but it should be remembered that you always add the acid to the water, and not the other way around. Also, eye protection is just good sense when working with this stuff.

Bill

[keelcooler]

Non diluted will degrade impellers and hoses.