31 bhm John deere 6068 running a little hot??

Surfishingboy

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I Purchased the 31 Bhm that was for sale on here with the 225 john deere. No complaints with the boat, in fact i love it. The only issue is the engine seems to run a little hotter then normal when I'm going against a strong tide. the engine will sometimes hit slightly over 200 degrees.

I called Cat and they said its not uncommon for the engines to get that hot during the summer months.

The boat has a Twin disc 507 2.5 gear, 28-26 prop.
Another thing i did notice is I'm falling short of the 2600-2650 rpm range and on the pin I'm hitting 2500. My ?? is do you think because the engine is slightly overloaded, that that will cause the temperature to run up like that. It stays around 195 when there's no drag. Any recommendations suggestions?
 

lobstercatcher

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I Purchased the 31 Bhm that was for sale on here with the 225 john deere. No complaints with the boat, in fact i love it. The only issue is the engine seems to run a little hotter then normal when I'm going against a strong tide. the engine will sometimes hit slightly over 200 degrees.

I called Cat and they said its not uncommon for the engines to get that hot during the summer months.

The boat has a Twin disc 507 2.5 gear, 28-26 prop.
Another thing i did notice is I'm falling short of the 2600-2650 rpm range and on the pin I'm hitting 2500. My ?? is do you think because the engine is slightly overloaded, that that will cause the temperature to run up like that. It stays around 195 when there's no drag. Any recommendations suggestions?

There are 2 boats set up like that in the harbor and one with a 2:1 and a 24 x 24 wheel . Both boats set up like yourshave developed heating situations. One is my brother in laws boat and head replaced the head gasket and head 2 years ago and it fixed the problem. The other same setup boat developed it last fall. The owner is also very picky about every little thing on the boat. He searched out everything and found nothing. He ended up calling in a expert and he found nothing. As far as I know he is still using daily and the was nothing done to the engine . I'll ask tomorrow what ever happened with his hotter than normal running temp. My brother in laws boat started using coolant which was a partial giveaway that something was up. The 2:1 boat has nothing wrong with it as far as I know ...other than lack of use.

If you think your bottom is starting to foul , try beaching it and cleaning the bottom with Clorox. If the engine is raw water cooled make sure your strainer is clean and the impeller is good .

PS: why did you call cat when you have a JD?
 
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lobstercatcher

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i meant i called john deere. The engine is keel cooled

keel cooled is better imo.

If the bottom is getting fouled or has slim or the keel cooler has mussels growth or something of that nature, it could cause the engine to run hotter.

Being that you are loosing rpm it could be a fouling bottom. Loosing RPM could be other things too but I'd chalk it up to a bottom condition starting.
 
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lobstercatcher

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Another thing you could check is the belt that turns the water pump. Make sure it is not loose. How many hours on the engine?
 

Surfishingboy

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2700 hours. Im heading out tomorrow and ill jump in the water and check the pipes and other things you mentioned.
 

fvashmarie1

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I have a 6076 300hp deere that runs 200 all day long when steaming and it was just rebuilt its only got 600hrs on it
 

lobstercatcher

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2700 hours. Im heading out tomorrow and ill jump in the water and check the pipes and other things you mentioned.

100rpm loss could be as little as a slimy bottom , the engine is working a little harder and summertime water temps. I probably isn't anything to worry about if everything checks out as good enough. 2700 hrs is still like brand new.
 

captainlarry84

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Sounds like it is time for a haul & bottom cleaning. I am sure that your keel cooler is slimmed up real good. Your motor with a 2.5 gear should spin that wheel th 2650.
 
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captainlarry84

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Easy fix it does not take much growth for the exchanger to lose its ability to cool. Mary Kay on-off works great to make the keel cooler shine like new.
 

traditions

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We had a 31 with a 260 cummins,2 1/2 to 1 gear and turned the same wheel as you with a cage.I have found that deeres will run a little hot if they are slightly over wheeled.Do you have walters coolers ?Have they ever been taken apart and cleaned?The DCA additive you should have in the coolant,or red premixed coolant,will coat the inside of the pipes and they will not transfer the heat as well.If you don't have pre mixed or DCA additive in your coolant,I would get some in there .The 6068 will erode the liners around 6000 hrs without it.The deeres I have had all ran hot,195 to 200 when steaming,but they were all heat exchanged.
 

thebridge

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I have a 6068 in a 30ft Osmond Beal. If I run open at 2500 RPM(for a good steam), my engine can get up to 195-200. Once I haul back its cooled back down. I have noticed it more since water temp is higher. Boat is also keel cooled.
 

hustler132

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I have a 6076 300hp deere that runs 200 all day long when steaming and it was just rebuilt its only got 600hrs on it
Thank you, I also own a 6076 300hp deere and it runs at 195 deg. F at 1800 rpm, I have not found anything to drop the running temperature.
I use Cool Guard II.
Paul
 

ARC

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I could be wrong but you might be swinging a bit too much prop
 
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