cold engine, top speed

[kkj]

In almost every piston engine application it is important to have the engine running in the right working temperature to minimise piston ring and cylinder wall wear. Usually as hot as possibly without boiling the water.<br />In the outboard world it doesn't seem to matter.<br />Full speed, top revs immediately, no thermostat, cold water flushing through the water jacket.<br />Does the outboard still last a whole season?

 

[DJ]

Re: cold engine, top speed

It is still important, in an outboard, to have the cylinder wall and piston temperature close to the same. Otherwise, the engine could suffer a "cold sieze".

 

[CATransplant]

Re: cold engine, top speed

Outboards last, depending on how they are maintained and used. I have a 47-year-old Johnson 35 hp. 47 years old. It doesn't look like the head has ever been off.<br /><br />It runs better than many newer outboards. Idles like a champ...pushing my boat along at less than 2 mph. Shove the throttle lever forward, and it planes out in 3 seconds, reaching 25 mph at WOT.<br /><br />It has a thermostat. It has a new thermostat. I warm it up at the dock before leaving the dock. I never run it wide-open for long, but cruise at about 75% throttle (20mph).<br /><br />47 years old. And I'm the umpteenth owner of this thing. It was hanging off the back of the boat I bought for $600. I didn't figure it would run. I paid for the boat and trailer.<br /><br />About three hours of work, though, and it fired right up. I can't imagine a 1958 automobile that had been sitting for three years would have been as easy to get going again.<br /><br />Outboards are great. Well-designed. Sturdy. At least the older OMC outboards are all that.<br /><br />I expect several seasons from this old outboard.

 

[Solittle]

Re: cold engine, top speed

Many if not most OMC 2 cycle engines will not idle well unless up to operating temp.

 

[kkj]

Re: cold engine, top speed

CATtransplant<br />So they have thermostats! I was reading another thread somewhere else and got the impression that engine temperature was of secondary importance.<br />About your Johnson 35: amazing! <br />Then it is hope for the Johnson 10 hp -58 I just got for $40. It has been unused for at least 2 years.

 

[Scali]

Re: cold engine, top speed

my 1994 40 Mercury 4 cylinder has no thermostat, not all do

 

[DJ]

Re: cold engine, top speed

Then it is hope for the Johnson 10 hp -58 I just got for $40. It has been unused for at least 2 years.

THere is plenty of hope. Those are just about bulletproof.

 

[naiscoot]

Re: cold engine, top speed

I am having trouble with my 150 mercury 88 tilt and trim. Does anyone know how to manually tilt the motor up? It is too heavy for me. Thanks, Eric

 

[CATransplant]

Re: cold engine, top speed

kkj,<br /><br />If it has compression and spark, it'll run. You might have to clean the carb, and you should change the impeller and put in new plugs (J4C, or J6C for lots of trolling), but if it has spark and compression, it'll fire up.<br /><br />These old johnnyrudes are amazing old outboards. They built 'em to last back in the 50's and sixties, and last they do.

 

[Paul Moir]

Re: cold engine, top speed

Another bookmark:<br />1958evinrude10hp.0catch.com/Evinrude1.htm<br />The thermostat on your '58 is hiding under the panel held on with three bolts on the head. Some outboards have them, some don't. The economy Johnny/Rudes since the 50s didn't while the good & larger ones do. Somehow it seem Mercury didn't get into them on any engine until the 80s I think. But I think you'll find a window into the difference between Merc and OMC in this regard. For example, have a look at the size of the impeller on an OMC 3hp. I think you could run that sucker dry for a week!

 

[kkj]

Re: cold engine, top speed

Thanks! That was an intersting site. Did answer many questions!!