2 questions about thermostats

[Squeakit]

Lake Havasu water temp is in the low 80's during the summer (now) and a local boat mech said it was OK to run without a T-stat while the water was warm, but put it back in during the winter. Opinions? My other question is why don't most of the small kicker outboards have T-stats? Comments?

 

[DJ]

Re: 2 questions about thermostats

Leave them in. You don't take the thermostat out of your car-do you?<br /><br />Many of the kickers do indeed have them.

 

[S.T. Marine]

Re: 2 questions about thermostats

Leave them in. Wont hurt the engine in any way!

 

[Squeakit]

Re: 2 questions about thermostats

Hi Djohns - thanks for the reply. Actually, I have removed the T-stat from my pickup and it runs alot cooler - what with 115 degree outside and running the A/C - but I don't think I'll run my OB without one (have a new one on order) as I searched this forum and couldn't find anyone with anything good to say about removing T-stat. I have a Force 50 on which I've installed a telltale - ran it the other day without the stat for about 30 minutes - you sure get great water flow without it, but with a Force, one shouldn't push one's luck. I have 3 small motors (2 are old 'rudes and 1 is a yammy) and none of them have stats. Just curious as to why not.

 

[Squeakit]

Re: 2 questions about thermostats

Thanks ST Marine - my reason for asking this was the other day I was talking to a guy with a Johnson V4 that pulled his stats 4 years ago and never had any problems - he felt that it cooled better and his engine sounded OK to me. Maybe he's just lucky??

 

[Hooty]

Re: 2 questions about thermostats

Your o/b and your truck were designed to operate their best within a certain temperature range. Not hotter, not cooler. That's what t'stats are for, not help your engine warm up quicker on cold mornings.<br /><br />c/6<br /><br />Hooty

 

[kart33]

Re: 2 questions about thermostats

Not to mention the increased temperature in the engine help with combustion and better gas milage is achieved. Lord know we need help in the milage dept.

 

[DJ]

Re: 2 questions about thermostats

Squeakit,<br /><br />I do not know what type of pickup you have, but you are not doing yourself any favors by running it without a thermostat. <br /><br />Todays engine controls depend on a narrow engine temperature range to deliver the best fuel economy and lowest emissions. Without a thermostat, you are sentencing the engine to forever run in "open loop" and are dumping raw fuel out of the exhaust system.

 

[Squeakit]

Re: 2 questions about thermostats

Thanks for the informative replies. P.U. is a 91 Mitsubishi 2.4L with multiport F.I. and my cranky little truck is a whole 'nother subject that's probably inappropriate for a boat motor forum. Would appreciate knowing what is meant by "open loop" - assume it means water is always circulating?? Thanks again.

 

[DJ]

Re: 2 questions about thermostats

Squeakit,<br /><br />"Open Loop" refers to the engine management system (computer).<br /><br />When in open loop, the engine is running on a preset set of parameters. In other words, the engine computer is ignoring the inputs from engine sensors and substituting values, just to keep the engine running-read RICH mixture.<br /><br />Closed loop, the one you want to run in, on the other hand, is when the engine computer sees that the engine is up to its designated operating temperature. Once the computer sees this, it will begin adjusting the fuel mixture according to the input it sees from various sensors, ie; manifold pressure/vacuum, oxygen sensor, throttle position, etc.<br /><br />Closed loop provides optimum fuel economy and lowest emissions output.<br /><br />The engineers that designed that system did not waste all that time, money, complexity and weight for nothing. When working properly, a "managed" fuel injection system is MUCH more efficient than a carbureted system with no feedback.

 

[Squeakit]

Re: 2 questions about thermostats

Thanks for the explanation, Djohns - I have replaced the engine coolant sensor with a variable resistor (carbon pot) which I can manually adjust for best drivability as the Coolant sensor has apparently failed - my manual gives resistance values for various coolant temps. Engine runs better now than it has in a long time, and check engine lite no longer comes on. Fuel mileage thus far seems unaffected. It's the equivlent of the good old fashioned manual choke. I'll probably replace the stat and see how that affects it. Again, let me apologize for discussing car engine on a boat motor thread. Computerized control is great, for the most part, but heat can affect electronic components and when things drop dead on you, you have no choice but to replace them and pay the price or walk. I believe the same is true of new outboards - when the black box fails, you paddle ashore and buy a new one at a huge price or you sit on the shore. Maybe that's why so many on this thread are fond of the old motors with their simple points/condensor ignition systems and carburetors that can be repaired at home for a fraction of the cost. The sophistication of today's modern engines is amazing and incredible, but don't try to fix them yourself. The environmental aspects are another issue but I know that I am bothered more by all the trash and garbage that inconsiderate idiots dump in the lake and all along the shore than I am by whether they are running a 2stroke or a 4stroke. Oh well. This is a great forum - sorry about the rant.

 

[ob]

Re: 2 questions about thermostats

the thermostat and its housing also serves to maintain water jacket pressure which is critical to engine cooling.If your motor has a tell tale indicator you will notice less powerfull of a stream exiting with thermostat removed.Leave it in or replace with new if you fear your is old or faulty.

 

[revo3956]

Re: 2 questions about thermostats

Also, I believe if the motor runs too cold won't carbon deposits build up quicker?