randomly occurring increases of engine temperature


 

Trevor,

Yes, you are correct about Johnson. Judy and I are fine, thanks.


CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar

On Sat, Sep 11, 2021 at 10:25 AM Trevor Lusty <trevlusty@...> wrote:
Hi Bill,
         This all came about due to taking a detour into the Amazon for a few months. Loads of silt in the water, even sixty miles out of the delta the water was still chocolate brown.
When I came to Ireland I was chatting to some of the local fishermen who told me it was quite normal for them to change out the seawater pumps on their trawlers as they often will plough through sand to get into various bays where they can get a good haul of prawns.
Am I right that the pump on that Yanmar would have been a Swedish make - Johnson?
Best to You & Judy.
Trevor


Trevor Lusty
 

Hi Bill,
         This all came about due to taking a detour into the Amazon for a few months. Loads of silt in the water, even sixty miles out of the delta the water was still chocolate brown.
When I came to Ireland I was chatting to some of the local fishermen who told me it was quite normal for them to change out the seawater pumps on their trawlers as they often will plough through sand to get into various bays where they can get a good haul of prawns.
Am I right that the pump on that Yanmar would have been a Swedish make - Johnson?
Best to You & Judy.
Trevor


 


Raw Water Pump Chamber Wear:
That is an interesting point. I searched for the diameter of new raw water pump chambers and could not find any dimensions for the Onan/Sherwood 702 pump which is on most Onan generators, the Volvo engines, and the Yanmar engines. I think this may be something that an owner would want to know. If any of you happen to have new pumps as a spare, please measure the inside diameter of the raw water pump chamber and reply.

Impeller Blade Wear at the Tip of the Blade:
I have never measured the wear to the inner wall, but have measured wear to the impeller blade tips and found a reduction in diameter of a little more than 2mm. This wear happens for 2 reasons: Hours of use and the cleanliness of the inner wall. The inner wall of a seawater pump will become crusty to the touch from the buildup of minerals. The more abrasive the inner wall is the more wear. The inner wall should be cleaned each time an impeller is changed with a combination of 600 grit wet/dry and Scotchbrite pad.

Sadly, many people think that impellers only need to be replaced when the blades tear off and the engine overheats. 
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CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar

On Fri, Sep 10, 2021 at 10:51 PM Trevor Lusty <trevlusty@...> wrote:
Jose,
       I had a similar problem. with the Yanmar engine in my SM for almost a year which drove me mad. Finally I bought a new sea water engine pump more out of desperation than discovering the actual fault.
When fitting the new pump I had the old and new pumps sitting together in the cockpit.  I thought I was imagining it, bit when I checked the old one with my callipers the chamber that houses the impeller was almost 2mm wider than the new one from wear. 
Fitted the new pump and the temperature returned to and stayed at 80C.
Trevor Lusty
Ireland


Trevor Lusty
 

Jose,
       I had a similar problem. with the Yanmar engine in my SM for almost a year which drove me mad. Finally I bought a new sea water engine pump more out of desperation than discovering the actual fault.
When fitting the new pump I had the old and new pumps sitting together in the cockpit.  I thought I was imagining it, bit when I checked the old one with my callipers the chamber that houses the impeller was almost 2mm wider than the new one from wear. 
Fitted the new pump and the temperature returned to and stayed at 80C.
Trevor Lusty
Ireland


Jose Venegas
 

Bob,
This is a good idea. I agree that in the tropics running the generator + water maker+ Bat Chargers can cause create a lot of heat. Increasing the air flow can only help. Also adding and pointing a fan to the high pressure pump of the water maker is something I have in my list.
Jose
Ipanema SM2k 278


rossirossix4
 

Just for the record--My Santorin which always had constant temperatures on its temp gauge (would change only with changes in ocean water temps) One time I noticed a 5F increase in engine temp.  An inspection showed my engine room exhaust fan had failed (it had been working when I checked for outflow during startup).  So it may have an effect but rather small.

Slightly related--I have always suspected that high engine room temps during generator operation has caused those expensive Onan control board failures.  Using the  dessalinator in the tropics whicle running the gernerator results in a great deal of heat in the engine room.  Because the generator combines a diesel engine with a somewhat air cooled alternator it manages to product quite a bit of heat and the feed and high pressure pumps also produce heat.  When making RO water I have gotten into the habit of leaving the cockpit floor open.   Because I have a 220V outlet mounted high on the forward bulkhead of my engine room I also have a small portable 220V fan that is pointed toward the dessalinator pumps.  I've also pointed it at the control panel of the generator at times.   The extraction fan, even after I replaced the capacitor is still relatively weak, and I believe a design error.  When we are running a generator we have PLENTY OF EXTRA power to power an exhaust and a much needed needed intake fan.  How about a dedicated 220 to 12V converter wired to the engine intake and exhaust fans.  Anyone have any ideas?

Bob, KAIMI SM 429


David Vogel
 

Hi Jose,

I would not think that the airflow in the engine room, fresh air in via the blower or exhaust fan, would significantly alter the engine operating temp, either as shown at the engine instruments (at the helm), or direct infrared observation of the oil temp (oil filter). FWIW, I see rock steady 80ºC at the helm, with the exception of periodic running at high-power (>3,200RPM, Yanmar 4JH3-HTE) after extended periods of running at low revs, in order to burn off any carbon build-up on the turbo (another lesson learnt). In the extended high-RPM scenario, I do see a trending rise of about 5ºC.

As Bill indicates in his very comprehensive answer, if you are seeing an intermittent increase in the engine OPR temp then Bill provides a good path to follow in troubleshooting a problem before it becomes more serious.

As an aside, I would heartily recommend any folks planning to proceed west from the Americas, to get such issues well and truly sorted before they even get to the Central America (e.g. Panama) as, once to you get there, even in pre-COVID times, the amount of time and energy to resolve even simple things can be astounding when compared to places where you have ready direct access to necessary parts and expertise.

Best,

David
SM#396, Perigee
Bay of Islands, Lau Group
Fiji



From: <main@AmelYachtOwners.groups.io> on behalf of "Jose Venegas via groups.io" <josegvenegas=icloud.com@groups.io>
Reply-To: <main@AmelYachtOwners.groups.io>
Date: Friday, 3 September 2021 at 6:40 am
To: <main@AmelYachtOwners.groups.io>
Subject: Re: [AmelYachtOwners] Engine Room Exhaust Fan / Blower - lessons learnt #lessons

David, you may have something here.  I have noticed randomly occurring increases of engine temperature up to 220F when running the engine above 2000 RPM.  However the temperature does not seem to drop after opening the engine-room  door  and have not been able to measure any temp in the engine higher the 176F with an infrared thermometer.  
Any thoughts?
Jose Venegas
Ipanema SM 278 
currently in Shelterbay PANAMA