Evinrude 100 HP wont idle after running.

willieM100

Recruit
Joined
May 29, 2004
Messages
4
My 1968 Evinrude 100 motor runs ok at the start. However after I run the boat for five or ten minutes at a higher RPM and then I want to decelerate to idle, its will stall or the motor will die. I have already tried choking it and pumping the fuel pump bulb but it does not help to restart. What is causing this
 

duck64

Petty Officer 2nd Class
Joined
May 25, 2004
Messages
144
Re: Evinrude 100 HP wont idle after running.

first i'm not a mechanic. i have a johnson 115 it got so bad it wouldn't even idle, i would try manual idle and try 2 or 3 times to get it going i don't no about decarbing so a friend of mine told me to buy some chemtron b-12 to put in gas tank (berryman) and change to synthetic oil $19 per gallon at walmart. i did and after first tank i couldn't believe it i have a new motor so next tank i did one more can. maaybe this won't work for you but it sure did for me.<br />goog luck
 

duck64

Petty Officer 2nd Class
Joined
May 25, 2004
Messages
144
Re: Evinrude 100 HP wont idle after running.

sorry willie it's b-12 chemtool
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: Evinrude 100 HP wont idle after running.

Do you have the t-stats in your motor? These motors do not like to idle unless at full operating temp.
 

duck64

Petty Officer 2nd Class
Joined
May 25, 2004
Messages
144
Re: Evinrude 100 HP wont idle after running.

yes i have t-stats it got so bad i was worried i changed the plugs did a compression check, as soon as i learn some more about seafoam decarb i may try that, but now i'm happy.
 

willieM100

Recruit
Joined
May 29, 2004
Messages
4
Re: Evinrude 100 HP wont idle after running.

Hey Dock bob, What brand of synthetic oil were you talking about? I was unable to find synth. oil at $19/gallon. Also is this just a one time treatment or do you run the motor all the time with it?
 

rottie2

Recruit
Joined
May 24, 2004
Messages
3
Re: Evinrude 100 HP wont idle after running.

Just a suggestion but did you check the vent on your fuel tank? I had the same problem 2 weeks ago. My tank has a manual vent but some are built in the cap. You may want to try to run it with the cap loose.
 

willieM100

Recruit
Joined
May 29, 2004
Messages
4
Re: Evinrude 100 HP wont idle after running.

Yeah I tried that I even took the cap off but it didnt work.
 
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