3.7/470 how hot should it run

[cswitch]

after many many hours finally got this motor runing cam seals rebuilt head and complete carb finally going to put in the water today hope all goes well but was wondering if any one knows the normal opp temp i have a 142 stat with the 3 inch exchanger i know i know i need a 4 inch but no money for that right now so ill just have to watch the guage close thx to all for the help

 

[stonyloam]

Re: 3.7/470 how hot should it run

Normal operating temperature, taken at the sender is 165 to 200 degrees F. With a 160 thermostat.

 

[cswitch]

Re: 3.7/470 how hot should it run

Ok three times around lake run perfect happy day it averaged 200 somtimes around 210 you think im still safe at that what would be the danger zone? ?

 

[stonyloam]

Re: 3.7/470 how hot should it run

Danger. Are you sure that your gauge is reading correctly? You have NO room for error there. Could try one of these: http://www.summitracing.com/search/...-Gasket-Thermocap-Radiator-Caps/?autoview=SKU

 

[cswitch]

Re: 3.7/470 how hot should it run

I replaced the sending unit and in the drain hole right next to it i have a autometer guage the both read the same would it hurt just to remove the thermostat? Just a thought i think im becoming a 470 fan lol i couldn't belive the power it had if its as good on gas as I've heard. It was only one weekend of work to fix 25 years of abuse lol and after a ton of help from the people here only cost 500 to fix ...yea the motor style ill admit is a little funny but so easy to work on

 

[stonyloam]

Re: 3.7/470 how hot should it run

Removing the thermostat will do more harm than good. You just do not have enough cooling. Pop the ends off the exchanger and make sure the tubes are clean. Seawater runs through the tubes and they can accumulate crud. The manual recommends cleaning the tubes with a suitable size wire brush. If you have not changed the impeller it might be a good time to do it.

 

[cswitch]

Re: 3.7/470 how hot should it run

I soaked and flushed the heat exchanger in clr
(The big round thing on the side) i belive thats it? I changed the im peller put a clear tube on the output so i can see if its flowing good its always full and moving lots of water is there anything else i can do to help it any tricks i have at least 150 psi in each cly did did the leak down test pressure checked the cooling system held fine didnt know if there was something i might have overlooked after reading many many post here i tried to cover all the checks i could maybe it just the nature of the beast. Is there a after market heat exchanger or a place to buy a 4 inch (cheap) i spent my budget getting it all fix wife getting mad ....

 

[EddiePetty]

Re: 3.7/470 how hot should it run

The CLR will not remove marine debris nor remmants of a former pump impeller. You MUST remove the fore and aft exchanger end plates to PROPERLY inspect/clean the exchanger.

Additionally, your exhaust my be restricted by pieces of a failed exhaust flapper (shutter). Remove the rubber joint aft of the elbow and inspect the inboard side of the exhaust for obstructions. Remove the prop and inspect the outboard side...you may have to remove the outdrive to extract any large pieces.

 

[stonyloam]

Re: 3.7/470 how hot should it run

Eddy is right on. If you can't get it cooled down e-bay is a good place, make sure it has the 4" brackets with it. Yeah they are not a bad engine if you are not afraid to work on it.

 

[cswitch]

Re: 3.7/470 how hot should it run

Ok great i havent checked the exhaust yet ill do that tonight didnt even think of that i did take off the ensa of the heat exchanger all tubes were clear do you think running a brass bruss on a drill threw them it didnt look bad at all nice and clean and if the flapper is broke and stuck what does it take to fix that or just clean it out and go? ? Thx again for the help

 

[EddiePetty]

Re: 3.7/470 how hot should it run

"...do you think running a brass bruss on a drill threw them it didnt look bad at all nice and clean and if the flapper is broke and stuck what does it take to fix that or just clean it out and go?...."

As the tubes have been 'CLR'ed, I'd just use LOW pressure air and a look-see with a good light for the tubes.

IRT the flapper and/or remains:
Check this diagram out:
http://www.marinepartsexpress.com/M... 1985-1986/6916779_0B434940/EXHAUST ELBOW.pdf
Remove the rubber hoses (pc's 1 and/or 7) to gain access to the inboard side of the exhaust. You're looking for remains of pc. 6. As previously stated, if the flapper/pieces are missing and can not be located in the inboard side of the exhaust, remove the prop and/or outdrive, as applicable, to examine the outboard side of the exhaust. Sometime the flappers will break into small enough pieces to pass through the exhaust and be ground up by the prop.

The jury is still out IRT replacing the flapper (search the archives). The flapper in our V-20 has been missing for years with (so far) no ill effects. Of course we are carefull to not chop the throttle nor allow astern wave action.

 

[solar7647]

Re: 3.7/470 how hot should it run

I sen you a pm about your heat exchanger