Re: Heat Soak...Cowl Vents?
1998 Evinrude 150 Intruder stalls after sitting in the sun
--------------------------------------------------------------------------------
My 1998 Evinrude 150 Intruder has all of a sudden started stalling when I shift into forward or reverse. It only does it after running for a while, then sitting in the sun for a while. It always cranks right up and idles perfect. In neutral I can rev it as high as I please, but as soon as I shift into gear it goes dead. From there it'll crank right up again, but do the same thing when I try to shift again. I can play with it back and forth and eventually get it to pick up, and it'll run great then. It seems to be after I've run for a while and then stop and sit for an hour or more. It doesn't do it when I first crank it up for the day (after sitting all night/several nights); and it doesn't do it if you run it, kill it, and crank it right back up. I called a repair shop and they said a new type of fuel was being sold to the US now and that it was designed for fuel injected motors and that it would cause a carburated motor to do this during hot weather. He said there is nothing I can do about it and that it would do it from now on - at least in hot weather. I don't know that I believe this because most everything else I own (ATV, lawnmower, weedeater,......) has a carburator and they aren't stalling under load.
abrazzel
View Public Profile
Send a private message to abrazzel
Find all posts by abrazzel
Add abrazzel to Your Contacts
#2 June 11th, 2010, 09:04 PM
Steven P.
Cadet
Join Date: May 2010
Posts: 17
Re: 1998 Evinrude 150 Intruder stalls after sitting in the sun
--------------------------------------------------------------------------------
It's been a number of years since I worked on one of these. Your problem is called either hot soak or heat soak. The fuel in your lines is vaporizing and your motor when it starts up is running on vapors . Google this to find more info. If you can,t find anything let me know and I will dig some info up for you.
bayouboatdoctor@aol.com
Thanks
Steven P.
Steven P.
View Public Profile
Send a private message to Steven P.
Find all posts by Steven P.
Add Steven P. to Your Contacts
#3 June 13th, 2010, 07:50 PM
abrazzel
Cadet
Join Date: Aug 2007
Posts: 4
Re: 1998 Evinrude 150 Intruder stalls after sitting in the sun
--------------------------------------------------------------------------------
Thanks Steven. I was able to find the best explanation to this problem so far by searching with the key words you provided. Here's what I found:
ETHANOL PROBLEMS
By Robert Van Brunt
Chief Petty Officer U.S.G.G. ret
ETHANOL AND VAPOR LOCK
Short description:
When the engine compartment becomes hot either by climate or idling, and you use ethanol-blend gasoline it can cause excessive vapors in your fuel line and starve the engine of fuel. The engine can run poorly or stop and will not run until the fuel condenses.
THE PROBLEMS
Vapor Lock
Fuel containing 10% ethanol is called E10. If you have ethanol in your gas, you run the risk of creating vapor lock because of excess vapors.
Ethanol ?boils? at 87?F (at normal atmospheric pressure) and turns from a liquid to a gaseous state. By comparison, most automobiles have their fuel pump in the gas tank, so the whole system remains under pressure unlike boats whose fuel tanks are vented. In a closed system, the higher pressure raises the flash point of the ethanol reducing the amount of vapor that is produced. In addition, most automobile fuel lines are outside of the vehicle allowing them to stay cooler.
Since most boat fuel lines are in the enclosed space (sometimes even insulated) of the engine compartment, normal ventilation will not cool the fuel significantly enough to avoid the potential problems of vapor lock. Furthermore, since the fuel pump in a boat is mounted on the engine (versus a car where the pump resides in the tank) the action of the pump can reduce pressure in the tank to below atmospheric pressure and further reduce the flash point.
Boat engineers are aware of this problem and are reducing the likelihood of this occurring by reducing the suction required by the fuel pump, minimizing hose fittings and bends, and including a quality anti-siphon valve. In existing boats, fuel lines and filters should be kept as low in the boat as possible and tank vents should be cleaned and open.
Heat Soak
Most boats have ?forced? ventilation. Air moves through the engine compartment when the boat moves forward. Heat soak happens after you have been at high RPM and then stop or drift on idle for a while. Because of heat soak the engine compartment will rise to a point where the ethanol will boil
THE CURE
To prevent vapor lock (i.e. boiling ethanol):
1. Make sure the engine compartment has adequate ventilation.
2. Relocate fuel lines to be low in the bilge. (The bilge is cooler because it is in direct contact with the water.)
3. Monitor the engine compartment temperature.
4. Add (or turn on) engine room blowers.
5. Keep the tank vent clean and unobstructed.
abrazzel
View Public Profile
Send a private message to abrazzel
Find all posts by abrazzel
Add abrazzel to Your Contacts
#4 June 14th, 2010, 06:10 PM
KailiNoel
Cadet
Join Date: Jun 2010
Location: Lindenhurst Long Island
Posts: 6
Re: 1998 Evinrude 150 Intruder stalls after sitting in the sun
--------------------------------------------------------------------------------
Hi...this is my first post but I have been reading the posts on this forum for a few weeks now. I have to say that the wealth of information here is just incredible and I have been able to solve a few small problems with little to no out of pocket expense by doing some research here. The "heat soak" issue seems to come up a lot and I think I am having this problem on my 75 Johnson 115. Im going out tomorrow and am going to take the engine cowl off before I stop running to see if it helps the engine cool off. Has anyone ever tried adding some vents to the cowl to help the hot air escape? I already purchased 2 from west marine but will only install them if removing the cowl helps. Also wondering if anyone knows if adding vents will have a negative effect on the air pressure required to keep the engine running at normal speeds/rpm's. Looking forward to your responses and thanks in advance!
KailiNoel
View Public Profile
Send a private message to KailiNoel
Find all posts by KailiNoel
Add KailiNoel to Your Contacts
#5 June 16th, 2010, 07:02 PM
Pursuit c/c
Cadet
Join Date: Jun 2010
Posts: 1
Re: 1998 Evinrude 150 Intruder stalls after sitting in the sun
--------------------------------------------------------------------------------
I am also having this hot soak problem on my newly acquired 92 150 evinrude.
Engine runs perfect after first start of the day. After a hot soak it will stall with the slightest amount of throttle. After nursing the throttle numerous times it will finally increase in speed and then act normal again.
I am going to try to find some non-ethanol fuel to see if this may be the problem. I'll let you know what I find...
