Heat Soak on carbed 175 hp Evrinrude

[ralph50]

New fuel pump

Carbs rebuilt

Engine runs awesome

Motor will run fine for hours and hours.

Shut it down and its a PITA to restart not to mention dangerous when maneuvering out of the sandbar and not hitting anyone.

1. I'm considering removing the t-stats.

2. Trying rec fuel (no ethanol)

3. Putting a vent in the cowling

I read somewhere about rebuilding the "vapor separator" but I'm not even sure I have one.

Thanks

[muzzy1127]

ralph, i see youre on a lot with smart advice. What type of fuel are you using?

Normally what "heat Soak" is when fuel begins to boil out of the carbs under the hot cowling. Then youre just stuck with vapor stuck in the carb bowls. I removed all of my insulation from my johnson 225 and ran ethanol free fuel and that solved some of my issues.

sometimes my wife would need to squeeze the primer ball until really hard to get the motor going at the sandbar I was always nervous id smack an expensive boat.

[mrdelgado]

quote:

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Originally posted by ralph50



1. I'm considering removing the t-stats.

2. Trying rec fuel (no ethanol)

3. Putting a vent in the cowling

I read somewhere about rebuilding the "vapor separator" but I'm not even sure I have one.

Thanks

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vapor separator = fuel injection

removing t-stats and running cold = carbon build-up

[ralph50]

quote:

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What type of fuel are you using?

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Shell 87 octane. I have not tried rec fuel yet.

quote:

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removing t-stats and running cold = carbon build-up

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I'm in Miami. Water temps are between 75 and 85 degrees. I was wondering how bad the carbon build up could be?

[ralph50]

Also can someone explain to me how the alcohol vapors actually cause vapor lock???

I assume that the alcohol boils in the carb float causing pressure and closing the float needle?

The carb basically thinks its full of fuel when in reality it is fuel vapor mix?

When the engine tries to start it actually sucks up the less combustible vapors?

If you pump the primer bulb it refills some but not all of the gas so you still have trouble starting etc?

I think I got 50% of that right.

[muzzy1127]

Ralph, you are right in in that the the ethanol will burn off, so what I always thought was the case was that the ethanol would burn off due to the extreme heat. resulting in having a lesser octane fuel sitting in the bowl. so even if you did pump up the primer ball you will have a lesser quality fuel. When my johnson suffered from the similar symptoms, Id always squeeze the ball on every start to "richen" the fuel octane. The engine would spit and spudder and id let it warm up for a few minutes before moving. probably until the crappy mixture burned through. When we were leaving a fishing spot, this was easy since id warm it up while pulling anchor and cleaning the deck. at the sandbar i was never really comfortable in essence i couldnt control the boat, knowing any bump in the throttle will result in me stalling.

I read for months when i had my johnson about vapor lock a lot made sense.

I did remove my thermostats, i did decarbonize my motor once a year with sea foam overnight.

I am in sarasota florida so i didnt care about the thermostat issues as well. and the old john/rudes dont care much about fuel consumption anyway. I didnt notice a difference there. I felt all the insulation on the cowling was just holding heat in so I ripped all the foam out.

right before i blew up my motor, we were working on insulating my fuel lines. to keep the heat away. from them, The issue is also the line that feeds the fuel pump as well as the small ones that feed the carbs, they get hot as well and raise the temperature of the fuel allowing it to burn off too.

I remember making air ducts from the cowling to cool my fuel lines etc. I tried almost everything and never truely solved the issue.

ultimately what helped me was paying to get my tank flushed by a fuel tank polishing service and switching to rec fuel. Honestly the motor never ran better than when i did that.

[ralph50]

Thanks for the info.

My main concern is also the sandbar. You can't even hear the engine over all the radios.

The engine will hopefully get me through a few more seasons before it dies.

Last year I blew a hole in a piston due to running lean but I rebuilt the carbs, replaced the piston and kept her going.

I will take out the foam and try the rec fuel.

Thanks

[michigan dave]

These engines do have a vapor separator, and yes alcohol will boil and cause vapor lock in hot climates. I fought a similar problem with a John Deere gas tractor for years before I discovered non ethanol fuel. I will bet you a new Mako hat that all you need to do is switch over to rec gas and your problems will go away. One other idea is to put a simple low pressure fuel pump inline before the separator and it might very well help.

Rec gas is the answer though.....

dave

[flounder]

quote:

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Originally posted by michigan dave


These engines do have a vapor separator, and yes alcohol will boil and cause vapor lock in hot climates. I fought a similar problem with a John Deere gas tractor for years before I discovered non ethanol fuel. I will bet you a new Mako hat that all you need to do is switch over to rec gas and your problems will go away. One other idea is to put a simple low pressure fuel pump inline before the separator and it might very well help.

Rec gas is the answer though.....

dave

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Adding to Dave's suugestion, you might want to read this.

http://www.onallcylinders.com/2015/0...ou-can-fix-it/

Hope it helps.

[ralph50]

The funny thing is that I am 1 mile from the ocean and the only rec fuels are either on the water at marinas or 10 miles away.

I need to burn about 40 gallons and then fill up with rec fuel.

Thanks

[Tinbanger1979]

I ran a 1993 Johnson 150 like yours for many years. The Johnson/Evinrude 60 degree carb motors all have problems with heat soak. The hotter it gets on the water the worse it gets. Best thing you can do is pump the ball up after you've been sitting. Other fisherman I've talked say that the white ocean runner motors are not as bad as the grey ocean pros,but they all have issues. All my carb loopers smoke like there on fire after sitting in the hot sun for a while. I switched to XD100 and the smoke went away.[]

[ralph50]

I have a love/hate relationship with this motor.

Took her trolling about 25 miles out.

Motor ran awesome for like 5 hours of running and trolling, running and trolling.

I'm in love again but I wasn't spearfishing which requires stop and go.

[uscgman]

Just to be sure, I would recommend buying another cowling to modify.

They are cheap enough that you can remove the insulation and add air vents without having to worry about destroying your good cowl if it is not the issue.

I would also recommend letting the engine idle for two minutes after a long hard run to let it cool down like a turbo diesel. When you shut off a hot heat soaked engine after a long run quickly the temp can go up.

https://www.ebay.com/itm/Johnson-150...BW7brZ&vxp=mtr

[ralph50]

I removed the insulation and drilled about 12 holes on the inside cover with a hole saw.

I don't think it made a difference.

My next step is to drain the tank and fill up with Rec 90.

[ralph50]

Rec 90 made a huge difference.

Started right up after each dive spot.(about 15 min each spot)

I had to prime the bulb twice but that was after shutting down for 2 or more hours.

Now I just have to find it cheaper than $4.60 a gallon.