08 yanmar 110 hp cooling

L

Lummisailor

Well-known member
Joined
Mar 30, 2017
Messages
69
Fluid Motion Model
C-248 C
Vessel Name
synergy
any one have suggestion's on accessing the raw water pump for an impeller replacement on the 110 hp Yanmar on the R25, other than paying a mechanic $125.00 and hour
n
 
This job takes less than half an hour on the Yanmar 110 HP. I've done it 8 or 10 times. I usually place a mat over the door threshold and lay with my feet in the cabin. All the work has to be done with just your right hand. I use a ratcheting screwdriver to remove the cover. Yanmar sells an impeller puller that then threads into the impeller.

I've participated in this job on other Rangers and believe that this engine has the easiest access of all.

Please send me a private message if you need more detail.
 
I agree with Rich. My 2008 110 HP R25 is a breeze to change especially because I took out the factory installed generator. With the generator muffler in place, it is much more difficult to access but doable with a nimble body. Of course that doesn't mean that it always goes smoothly. I have had issues with the impeller not being installed properly such that after a few seconds of operation it quit pumping. I never have gotten to the bottom of that. I even sent that impeller back to the distributor after I found my old one worked every time I reinstalled it. The dealer sent it back and said the new one was totally in spec. For a project like this, I always figure that I can bumble through it just as well as a $125/hr mechanic - in general, they don't do magical things, they just work though the inevitable problems.
 
Thanks Rome and Still Crazy, I am going to take a shot at it . Will let you know who it goes.
 
To Roam and Still Crazy
Thanks again for the explanation on replacing the raw water impeller. The yanmar impeller has threads in the hub and the previous owner of our R25 left spare impeller as well as the removal tool that worked very well. He also left the dry run pump cover that has the Teflon disk and the knurled screws .Am now fully recovered from the bruised sternum caused from laying across the cabin threshold. :lol:
Pura Via Larry on Synergy
 
Well I replaced the raw water impeller and the Thermostat (Yanmar recommends replacing after 1000 hrs.) The engine temperature still increases to 210 deg. at 2600 rpm and up. So next project is descaling the heat exchangers. Like the song Getting To Know You, Synergy and I are becoming very familiar with one another.
Pura Vida Larry
 
Are you sure the coolant level is full? The only way to know for sure is to take the “radiator” style cap off at the very top of the engine. In our 150 hp Yanmar it’s right under the cabin/cockpit wall.
 
scross":1fb5elhx said:
Are you sure the coolant level is full? The only way to know for sure is to take the “radiator” style cap off at the very top of the engine. In our 150 hp Yanmar it’s right under the cabin/cockpit wall.
Click to expand...


once off, and you look, what should the coolant level be..

My RC25 will run all day at 2800 RPM and stay at about 200, but once I push it up to 2800 or above she hits 210 in a few minutes.

I've read the articles on burping and remain confused.
 
Coolant should be full right to to the very top. You don’t want any air in there at all!
Doesn’t matter that you have coolant in the overflow tank, you might still have air in the system if you haven’t filled it from the top cap.
Those temps in a Yanmar 150 hp at those RPMs are higher than mine. Could be an overheating issue or just differences in our gauges accuracy.
 
I just went thru this issue last year a few things I did was to replace the impeller in the circulation pump it was bad.. The is a service bulletin on the heat exchanger about holes not being aligned. There is a copy in my album.Mine was not in alignment and gasket number 11 was bad. That was the main problem I believe, I now run at 175 degrees at 2200 to 2800 all day and at 3000 it at 185 degrees. To burp it I removed the heater return hose at the t stat and filled coolant that way with the key on so the circulation pump would do the work.
 
scross":zvql8w1w said:
Coolant should be full right to to the very top. You don’t want any air in there at all!
Doesn’t matter that you have coolant in the overflow tank, you might still have air in the system if you haven’t filled it from the top cap.
Those temps in a Yanmar 150 hp at those RPMs are higher than mine. Could be an overheating issue or just differences in our gauges accuracy.
Click to expand...


Thx
 
Well as you may recall the last episode of the tail of overheating Synergy's Yanmar, I replaced the T stat, raw water impeller to no avail. Have now finished descaling the raw water system. Rather than removing the heat exchangers I connected the sea water intake hose to a recirculating 120 volt pump placed in a five gallon bucket and removed the outlet hose from the exhaust mixing elbow and placed in in the bucket. I mixed the product Barnicle Buster five to one and flushed for three hours. The sea trial was a one hour run to our mooring on Lummi Island from Squalicum Harbor launch ramp. At 2800 rpm the temperature was as close to 195 as I could determine some improvement. The only thing left to do is replace the antifreeze/coolant. and yes the mixing elbow is not clogged.
Pura Vida Larry
 
After disassembling the heat exchanger three times ,the over heating problem has been solved. It appears the factory assembled the inner bundle 180 degrees from the intended position in the outer tube. There are air vent holes that must face up to prevent air lock. The first two times it was reassembled the mechanic put it in as he had noted it's position prior to disassembly. I can now run at three thousand RPM (not that I want to)and temperature remains between 175 and 180.So we can now cruise at eight knots instead of seven . (note) it used to over heat at any rpm over 2400.
 
note, above report on solving cooling problem submitted my lummisailor has changed names to synergy
 
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