Running too cool - need specific thermostat

[brodie123]

Hi All. My Mercruiser L6 250 4.1 L is running too cool. Be aware that this engine was rebuilt and upgraded to a 4 barrel carb.

What's happening is when I am able to heat the engine up a few extra degrees (long run below planing speed) - she get's up to around 145+ degrees and there is a significant performance increase. I believe from the fuel vaporizing a little more in a warmer intake. Normal running temp "appears" to be just below 140. The thermo in there is new.

I've tried to find a thermo at around 160+ (stock is 140 which are easy to get). I've shopped everywhere but cannot find one. The 160's (or any other) are of a different style. (larger)

Before I make some form of adapter - or inline thermo - does anyone know where I can get a 160+/- thermo like the one below ??

Thx

 

[alldodge]

Hi All. My Mercruiser L6 250 4.1 L is running too cool. Be aware that this engine was rebuilt and upgraded to a 4 barrel carb.

What's happening is when I am able to heat the engine up a few extra degrees (long run below planing speed) - she get's up to around 145+ degrees and there is a significant performance increase. I believe from the fuel vaporizing a little more in a warmer intake. Normal running temp "appears" to be just below 140. The thermo in there is new.

I've tried to find a thermo at around 160+ (stock is 140 which are easy to get). I've shopped everywhere but cannot find one. The 160's (or any other) are of a different style. (larger)

Before I make some form of adapter - or inline thermo - does anyone know where I can get a 160+/- thermo like the one below ??

Thx

Unable to find the style in the pic but here is one which indicates it is for the 250 L6 engine
http://www.summitracing.com/parts/emp-300/applications/make/chevrolet/engine-size/4-1l-250

IMO a 4-barrell carb on that engine will do nothing except cause you to burn more fuel, unless you have done some major changes inside

 

[brodie123]

Thanks for the link - I don't see the size specs so I don't know if it will physically fit.

The 4 barrel was one of many changes (cam etc.) - I was able to go up 2" on the prop while maintaining the same RPM - also under load (skiing) she has more torque. love it!

 

[alldodge]

Thanks for the link - I don't see the size specs so I don't know if it will physically fit.

The 4 barrel was one of many changes (cam etc.) - I was able to go up 2" on the prop while maintaining the same RPM - also under load (skiing) she has more torque. love it!

Looks like you did the work to be able to use the carb.

What year is your engine?

 

[alldodge]

The thermostat I linked to is the standard 2 1/8 diameter, so probably won't work. Still looking but your engine year would help

 

[Fun Times]

Hi there, since your going outside the box of stock and looking for something a bit different, your thermostat sort of reminds me of a Volvo Penta thermostat that is more in the 160 range like this one. http://www.weserbootshop.de/Thermost...olvo-Penta-71C

And more importantly, if it turns out to be what your looking for size wise, it's also available here at iboats.
http://www.iboats.com/Volvo-3856961-...view_id.467892

You may have to walk your thermostat housing into an auto store like NAPA auto to find something that would fit.

Mercruiser part number 47594 is a bit warmer at 143 vs your stock 140. http://www.iboats.com/Thermostat-Sie...view_id.171849

Good luck.

 

[thumpar]

I would take it to NAPA along with your engine serial number. They are pretty good about figuring things out.

 

[Scott Danforth]

look at the stant catalog. they made most of the thermostats and caps that went into the engines from day one.

 

[brodie123]

Thanks everyone for all the feedback and sorry for the late reply. The engine is mid 80's.

I've been to Napa with no luck.

Thanks for the links!! I think I should be able to find a match there and order a couple in.

And yes, the engine was rebuilt for the purpose of more vrooom! lol All the help came from iboats forums!