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Does 24:1 mixture run cooler than 50:1?

cjbrill715

Regular Contributor
Hi everyone. I have a 1965 40 hp Super seahorse. I know it runs 50:1, but I started it yesterday to let it run on 24:1. It ran for a good 15 minutes but the exhaust wasn't giving off any water discharge. The impeller was recently replaced, and the power head was warm, but I was able to touch it, maybe 120 degrees I'm guessing. So i'm wondering if the 24:1 mixture made it run cool enough not to open the thermostat? Or does it need to be running at speed to warm up enough? Any info would be greatly appreciated.
 
This should be interesting.-------Was the motor running with a load or just idling.----Have you checked / tested the thermostat and valve underneath the thermostat ??----What was the ambient temperature ?
 
We are not sure if there is a thermostat and control valve installed in this motor at this time.------Posters have to answer questions and present more facts.
 
I agree and it is up to US to throw more questions ..........as you and I are both good at that. When I go see the doctor, ha asks plenty questions before he makes an accurate determination/diagnosis. But our OP brings up an interesting question about mixing ratio and heat. But in a four stroke racing engine....... and we have run many dyno tests...... I assure you that the highest quality synthetic oils will produce more horsepower as well as torque by providing less friction. Furthermore the thinner the oil, the more horsepower and torque.
 
When that motor is running properly and at full speed, the flow of water out the back of the motor should be substantial....similar to what would come out of a garden hose with the spigot wide open. I don't see any reason to run that motor at anything but a 50 to 1 fuel/oil ratio.
 
We are not sure if there is a thermostat and control valve installed in this motor at this time.------Posters have to answer questions and present more facts.

Sorry for the lengthy delay....I've had an interesting week. long story. The thermostat is installed...(new one I put in). I took the housing apart and found that the rubber gasket under the plastic thermostat housing that the check valve seats on was deformed and letting water down the auxillery passage that the check valve is in. I replaced it. Now it gives off a fine vapor/mist at idle, I haven't yet had a chance to see what the flow looks like under load/at speed because boating is illegal in MI right now because o the virus.
 
Crazy, thanks for the update. I have seen this happen before. Why can't you go for a boat ride? It's okay in MN, but still ice on most lakes up north here.
 
Crazy, thanks for the update. I have seen this happen before. Why can't you go for a boat ride? It's okay in MN, but still ice on most lakes up north here.

Our Michigan governor is a flaming Nazi....She is absolutely ruthless. Can't buy paint, garden supplies, from most stores, or use gasoline powered watercraft. Only God knows why. Our state is full of protests and civil unrest right now.
 
That's a "given". We had to also consider collection of oil on right side of engine. 3/8 mile ovals are pretty tight at 80 mph. Our Dyno and dirt track engine results prompted Amsoil to offer lower viscosity racing oil. When we first tested, we brought dyno results from the very first Wissota 400 hp Street Stock GM, to Amsoil with their 20/50, vs. Gibbs 10/30. The numbers convinced them to create a low viscosity racing oil. The MOTOR COULD NOT CREATE 400 HP with the 20/50, but the Gibbs produced 402 h.p. Best we could pull on the 20/50 was 396 h.p. Racers had been "watering down"....so to speak, the 20/50 with 10/30 regular synthetic Amsoil, because they were getting free Amsoil as sponsorship. We used Line Automotive (Lance) in Wright MN., Dad and brother to the drag racer Line. Amsoil had already been working on a low viscosity race oil, but they came out quicker once they saw the results we produced, as well as loosing business to Gibbs....a very fine product as well. Our Super Stock Wissota uses only a Holley 500, with stock GM intake. Compression ratio is unlimited and we achieved 14:1 by angle milling 2.02 camelbacks. In 2009 or so, a certain aftermarket head was allowed because the ole camelbacks really became a precious commodity. The aftermarket heads created an easy 390 hp, but never eclipsed 400 on either torque or horsepower. My brother lost the shop to the bank, but only because he kept borrowing money on the shop to finance his failing mortgage business. I got nothing out of the deal but grief and experience. Burned up almost all my 350 Chev cores and all but a handful of camelbacks. I'm probably talking "Greek" here to anyone under 50 years old, eh?
 
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