Engine temp

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Bill The kid

Veteran Member
Joined
Aug 22, 2018
Messages
30
Location
United States
Vessel Name
SEA FOX
Vessel Make
1978 Mainship Trawler
I have a 78 mainship with a T6-354 perkins what is a good running temp . i am at 180 running. when i run it at 2000 rpm the temp go to 200 to 210 then when i slow down the temp drops to around the 180 temp is this ok

what is the top speed on this boat is it 13 knots ??? thanks BR
 
Your temperature shouldn't rise. Things to check in this order:
Coolant level
Clogged strainer(s)
Raw water impeller (to see if any vanes are broken)
Clogged raw water tubes running through the heat exchanger
Clogged tubes in the transmission cooler
Clogged holes in wet exhaust elbow.

Ted
 
Hi it only go up when i put the fuel to it when after a slowing down it goes down to the 180 s . that should the temp BE AT ???
 
My 40hp Mitsubishi (10 yrs old) has always run about 195-200.
Temp goes down only about 5 degrees going slower.

Kid,
How much pressure are you running? And do you have an oil cooler?
With 13lbs or more 210 shouldn’t be a problem.
With your Perkins 185 to 190 would probably be a little better. I’ve read on TF of many running 170. I’d call that too cool.
 
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I don't think i was out of the park here just making shore what i should be looking for thanks Br
 
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My Perkins 6.354 NA was running around 195. I just worked on raw water pump. Changed out cam,impeller and end plate. Now running 185 .
 
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Well, jumping from 180 to 210 when you put load on it is too much. Maybe 10 degrees is ok, but you have a problem with your cooling system or raw water system and it will only get worse.


O C Diver gave a good list in his post above to check out.


David
 
My 54hp Yanmars run within a few degrees of 175 from 800 all the way to 2800 RPM.
 
Like Dave posted, common for many engines to rise 10F between light load and full load. Rising 20-30F is a problem. Some only rise 5F.

Some engines sub-cool at idle, not counting that.
 
"what is the top speed on this boat is it 13 knots ??? thanks BR"

"Top Speed" usually takes full throttle .

As these are NOT industrial rated engines , cruising or operating at full throttle may be very expensive maint. wise.
 
As several others have said there appears to be a problem. As a general rule when heading back to my slip I do a 5 min WOT run up and check oil, gearbox, exhaust, shaft seal and coolant temp. Over the course of a few months I noticed my coolant rising from 5 degrees to 10-15 over normal. The raw water impeller was 18 months old and looked fine. I replaced it and reversed the cover now it it’s back to 5 +/- increase at WOT. your engine is giving you a warning, don’t ignore it.

Don
We months I notice
 
I ran one of those Perkins in a 78 Mainship for many years.
At 2000 rpm the temp should still stay around 180.
Mine never climbed until I got to around 2200 then it would rise about 10 degrees.
You have a list of things to look at.
ADD the raw water exhaust manifold. I "rodded" mine out with a coat hanger 2 times while I owned it. I also had a piece of zinc from the heat exchanger get stuck in the inlet to that manifold.
I never saw 13 knots at WOT. more like 11+.
Good luck with the boat.
 
If you haven't opened, inspected and cleaned the raw water system you should. Hoping and "watching" are how expensive repairs begin. Do what OC said then you can sleep well.
 
If you had the cooling system of an engine two or three times the size the coolant temp probably wouldn’t vary at all above about half throttle.
But if your coolant is too eager to rise in temp then some component of the system is limiting the ability for the cooling system to cool the coolant. Sounds cool huh? haha. Put another way the coolant temp is too sensitive to load.

When I see that on my boat I need to rod out the flues in the coolant heat exchanger.
 

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