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  Atomic 4 Operating Temp (whippet)
Posted: 5:03:32 pm on 5/27/2012 Modified: Never
 
Hi

In my first year of owning 1981 mkIII.  Has gas A4, I assume original. Operating temp goes to at least 200-210F (according to cockpit gauge) even with light revs on engine.

I have snooped around google, and i think my first course of action is to contact Moyer and replace thermostat. Seems they also sell an input value that adds some backpressure to make thermostat more effective.

Appear to have good water intake and good water exhaust out the transom.

Any words of advice out there?

Thanks

Steve
TS&CC, 1981 MkIII
Toronto ON

  Re: Atomic 4 Operating Temp (dmartis)
Posted: 2:39:30 pm on 5/28/2012 Modified: Never
 
Yikes! 200F sounds pretty hot, as boiling temp of water is 212F.  Have you tried removing the thermostat (located at the front top end of the cylinder head), running the engine without it, and maybe putting the thermostat in boiling water to see how it operates?  This help you determine if the gauge is faulty, or if indeed the thermostat is faulty.

My A4 runs about 160F most times, and I don't have the input valve installed.

Dan Martis
Dream Catcher
Oakville, Ontario
Mark 3, Hull #636
  Re: Atomic 4 Operating Temp (whippet)
Posted: 3:11:45 pm on 5/28/2012 Modified: Never
 
Thanks, #636

i have since read on Moyer forum that a number of guys regularly run without thermostats, so i will certainly give that a go at next sail.   They claim there may be a tradeoff w less engine life -- but suspect 210F isnt so good for engine life either.  

Steve
TS&CC, 1981 MkIII, Hull 886
Toronto ON

  Re: Atomic 4 Operating Temp (wrapper)
Posted: 12:30:10 pm on 5/29/2012 Modified: 11:51:09 am on 6/13/2012
 
If there is white stream coming out of the exhaust, then she is probably over heating.  

I generally run at 160 to 180 tops.

This year my a4 was overheating (180 +) and I had to reverse flush and that seemed to stopped the over heating.

Allan
Cygnus
C&C 27 Hull 518



Updated June 13.  No more overheating.
  Re: Atomic 4 Operating Temp (larrybayer)
Posted: 12:16:50 pm on 6/1/2012 Modified: Never
 
Steve;

I have had a similar problem and finally trying to tackle it, so it might be of interest to you. One difference with my boat is that I have fresh water cooling.
However, quite a few years ago my temp gauge went sky high. I checked things over and didn't feel it was overheating, but just in case removed the thermostat which they say not to. I believe I had to make up an extra gasket to do this so that the casing wouldn't leak as the thermostat provides part of the gasketing. [I think} Anyways, it's ran that way for years with no problem. Last month I decided to fix/repair this situation as my son now uses the boat alot and I think it best to have the gauge working again. I also decided to switch the ignition system from points to electronic. So I contacted Moyer Marine parts department at 610 421-4436.The guy I talked to was super informative[ I forget his name, but anwsered both times]and not pushy about selling me stuff. Yesterday, I received the required parts he suggested to purchase first. A new temp gauge and sending unit as these are matched items so replacing one at a time doesn't do it. He talked me out of the thermostat purchase for now until I install the new parts and get some accurate readings. However I do believe that I will purchase the [expensive] stat down the road. According to him, running without the stat causes the engine to run lower than normal temps and it will build up large internal deposits eventually as you'll never reach running temps motoring out to the race course and back, however due to your own type of usage or lake water temperatures you might reach good operating temperatures. I think I've been fortunate in a way, since I have the fresh water cooling and usually have to motor at least once a season across Lake Ontario on way to a regatta at close to full throttle with a Max prop that loads her up pretty good. I hope to install the goodies this weekend so I might then have some more insight into this. I'll also be able to comment on the electronic conversion which he persuaded me do do cheaper than I was originally going to do. He talked me out of replacing the entire distributor shaft as he stated that there well over built and never seen them really worn unless the engine endured a seizure or other major catastrophy. Another item I ordered due to the age of my boat [1976, hull 682]was a new full pump. I decided to stay with the mechanical one rather than electronic for my own reasoning, but the reason for change is most important! Apparently the diaphram in the pump degrades over time and can cause fuel to dump/siphon into the crankcase and cause catastrofic results! as you can imagine, so for cheap insurance I'm giving Yogi a new pump. I've rambled on quite enough, but one point I'd like to make, is that if anyone really has questions about their Atomic Four, call the experts at Moyer and get first hand expertise!!!!!

Larry Bayer
Yogi Bear, Mk III
Niagara-On-The-Lake, ON

  Re: Atomic 4 Operating Temp (whippet)
Posted: 2:13:09 pm on 6/1/2012 Modified: Never
 
Captain Yogi Bear

I really appreciate all your advice and i like the long stories.  Feels like i am not alone in solving puzzles.    Through wonders of google, i previously located Moyer as a source, and you are right, they are super helpful.   Below is the note that i got back from Don the owner.  I am anxious to dig into his diagnosis when it stops raining on other side of lake from you.   Will inform what i find.

Also thanks for notes on electronic ignition and fuel pumps.   those are on my list.   i havent had this much fun since working on my 1973 Plymouth Valiant slant 6.

_________  
Hi Steve,

I wouldn’t buy anything at this time.  With good flow of water out of the transom (I’m assuming a late model engine), your high temperature is more likely caused by a localized restriction, probably in the “T” fitting or diverter cap in the middle of the water jacket side plate.  A restriction in this location will force water through the by-pass loop instead of through the engine block and head for cooling.  

You can test for this condition by simply closing off the by-pass loop using a small “C” clamp or vise grip pliers.  If the temperature comes down, it would pretty much confirm the “T” fitting and diverter cap as the culprit.

You can get a good idea of how severe the restriction is by keeping an eye on the water coming out of the transom.  If, as you slowly close off the by-pass loop, you start to lose water out of the transom, the restriction would be quite severe.  If the temperature comes quite quickly and you don’t lose much water out of the transom, the restriction would be relatively minor and you could remediate the condition (at least for now) with a by-pass restriction kit and get on with your season.  However, it this does turn out to be your case, you should schedule a removal of the side plate for checking and cleaning.

Don      

Steve
TS&CC, 1981 MkIII, Hull 886
Toronto ON

  Re: Atomic 4 Operating Temp (chriswheat)
Posted: 10:13:15 pm on 7/8/2012 Modified: Never
 
Right off the bat let me confirm that those guys at Moyer Marine are the best friends an A-4 owner can have. That said, mine overheated 2 years ago because the exhaust manifold (no doubt original from 1972) was clogged with scale that had finally broken loose. I took it off, brought it home, soaked it in diluted muriatic acid for a half hour or so, and flushed it out real good repeatedly in both directions. The result is an engine that runs at the temperature it should. That may not be your problem, but if your exhaust manifold is old you should flush it.

Chriswheat Second Wind


Chesapeake Bay MD

  Re: Atomic 4 Operating Temp (Capt’n Tom)
Posted: 9:35:35 pm on 7/9/2012 Modified: 10:09:40 am on 7/11/2012
 
Please explain how to reverse flush. Aries is overheating.  I have replaced the failed impeller and removed the thermostat and checked the hoses for blockage and continue to have overheating.
Suggestions?

Tom Ellis
Aries ‘76 C&C 27
The Blue Mountains, ON


[Google the phrase 'reverse flush atomic four' to get a selection of detailed instructions on the task, ranging from acid flushing through pressure flushing to simply backwashing. - Admin]

  Re: Atomic 4 Operating Temp (chriswheat)
Posted: 10:41:29 pm on 7/10/2012 Modified: Never
 
if memory serves, I removed the hose where the water exits the exhaust manifold to find that there was very little if any water getting through, so I pulled the hose going into the manifold to find plenty of flow. I then took the manifold off, and got the proper plumbing fittings from the hardware store to fit my garden hose to either end I wanted. I soaked the manifold in a 5 gallon bucket of diluted muriatic acid (mostly water) for about ten minutes, then hooked up the hose and flushed out lots of crud. Switched the hose to the other end and did it again. Repeating until all was clean and clear. Got a new manifold gasket from Moyer and put 'er back together. I didn't want to reverse flush with the manifold installed as that would just clog the engine. But make sure the manifold is not passing water before going through all that.

Chriswheat Second Wind


Chesapeake Bay MD

  Re: Atomic 4 Operating Temp (Capt’n Tom)
Posted: 10:34:58 am on 7/23/2012 Modified: Never
 
thnx Chriswheat.  Checked both exit then entry hoses to exhaust manifold and found very little water flow in both. It would appear problem is situated before the entry hose. I have ordered thermostat from Moyers and expect delivery this week.

Tom Ellis
Aries ‘76 C&C 27
The Blue Mountains, ON

  Re: Atomic 4 Operating Temp (sony2000)
Posted: 6:06:50 pm on 7/23/2012 Modified: Never
 
Capt. Tom, since you are this far, can you remove the access plate behind the alternator. The T fitting going in to the plate could be blocked, and behind the plate there will be a lot of rust flakes. Enough to fill a cup. From in there you can poke up into the head passages for rust blockages. Replace plate with a gasket or quality silicone. Sometimes the plate and or T, is finished. Try to use stainless bolts afterwards.
  Re: Atomic 4 Operating Temp (Capt’n Tom)
Posted: 11:43:45 am on 8/8/2012 Modified: 1:00:07 pm on 8/8/2012
 
Chriswheat and contributing Forum members. Problem finally solved!
Review: Engine was overheating-200 degrees plus. Checked impeller. It had failed. Found and removed impeller and small impeller pieces in water pump opening. Replaced impeller and thermostat (Moyer Marine) and replaced all cooling system hoses. Still overheating. Removed engine access sideplate, vacuumed grit out of opening. No impeller pieces found in side engine compartment. Checked water flow into exhaust manifold-very little water flow. Engine still overheating 200 degrees plus.
Closer inspection of impeller cavity/hose connection. Probed opening with small steel/hooked pick and pulled out small/folded over rubber impeller piece that was blocking adequate cooling water flow. Replaced impeller. Engine now running at 160 degrees. Good sailing again!
Thanks for your suggestions and support throughout this frustrating problem.
This Forum is so helpful. Thanks again!
Tom Ellis

Tom Ellis
Aries ‘76 C&C 27
The Blue Mountains, ON




[What makes the Forum really useful is when we get follow-up like this. Contributors' conjecture about the problem and personal troubleshooting steps are an important step toward a fix here, but a detailed description of the on-engine troubleshooting steps and achievement of a real solution are invaluable. Thank you, Tom - Admin]
  Re: Atomic 4 Operating Temp (larrybayer)
Posted: 10:52:27 pm on 8/15/2012 Modified: Never
 
Glad to hear you solved your overheating problem!
So, I finally installed the new electronic ignition kit from Moyer Marine. It was very easy, just followed their instructions and never had to touch the timing at all. Fired right up and ran like a charm!
Next, replaced the water temp gauge and sending unit. Went out for a run and the temp went sky high again right up to the 210 mark at just over half throttle. Haven't had time to dig into my problem yet, I've just been sticking close to home racing so I just putt out and set sail quickly. I had the internal impeller break on me last year and fortunately a 30 owner warned me about the impeller pieces loging in the bend just above the housing. I managed to pull out all matching pieces so I feel that should be good there. However, maybe the new impeller has bit the dust to?? Anyways, will dig into it hopefully this Sat.if my bruised ribs allow me to cram into the locker. [I've decided to retire from waterskiing] Great to hear the clues about the manifold and "T" fitting. I'll be looking into those also. Because I have the fresh water cooling I'm also going to bypass that to insure that it's not my problem? Will get back when I finally figure it out.

Larry Bayer
Yogi Bear, Mk III
Niagara-On-The-Lake, ON

  Re: Atomic 4 Operating Temp (whippet)
Posted: 5:46:10 pm on 11/1/2012 Modified: Never
 
Hi

Apologies for not closing loop on overheating issue.  Issue was as simple as stuck thermostat.  I ran all summer without it and temp gauge stayed pinned on cold.
I also took Don Moyer's advice and pinched off by-pass loop, and still got good water volume out the transom exhaust -- so engine ports seem to be clean.  

Seems there is some controversy whether running without T-stat does any harm.  Not to tempt fate, i just bought one from Moyer and will go in next spring.  

Now unto next issue.   During winterizing I unscrewed brass plug out of manifold to drain water.    Now in putting back, i cant get threads to mesh.    Plan A is new brass plug.    Plan B is re-tap manifold.   Plan C is JB? Weld to seal it up for good.  Any similar experiences?

Thanks to all for great thread.

Steve
TS&CC, 1981 MkIII, Hull 886
Toronto ON

  Re: Atomic 4 Operating Temp (sony2000)
Posted: 6:19:31 pm on 11/1/2012 Modified: Never
 
Teflon tape on a new plug should do the trick.