1974 115 evinrude quits after 15 minutes

[graco]

Have a 1974 115hp evinrude starts and runs fine, but when at full throttle for 15 minutes completely dies, will not start.The following day starts up fine and same thing happens. Any idea?

 

[glassmaster68]

Re: 1974 115 evinrude quits after 15 minutes

make sure your tank is vented,no vent causes a vaccum air lock,it would stop your fuel flow after about fifteen,,,,,,,,make sure you have a good line from tank to motor,,if your using a primer bulb hose,,they can go bad and have tiny leaks to lose your prime,,,good places to start anyways,,,,

 

[Joe Reeves]

Re: 1974 115 evinrude quits after 15 minutes

If the above vent test checks out okay, the problem may be electrical and if so, do the following.

Disconnect the black/yellow wire from the powerpack. Now, if the problem ceases to be, the usual problem is a intermitent short or voltage leak within the ignition switch, in which case rplace it.

NOTE: With that black/yellow wire (kill circuit) disconnected, it will be impossible to shut down the engine via tyhe ignition switch.

 

[emdsapmgr]

Re: 1974 115 evinrude quits after 15 minutes

Joe's right could be ignition related. Weak ignition components tend to fail when the engine gets up to normal operating temps. Unlikely it is the 4 igniton coils. I'd check the stator, timer base and the power pack-all expensive components. The factory service manual has a good ignition trouble shooting section and considering the cost of the parts-some time troubleshooting is a good investment.

 

[Joe Reeves]

Re: 1974 115 evinrude quits after 15 minutes

Having second thoughts along the line that Glassmaster suspects (fuel restriction), if the problem is not an ignition problem as per my previous reply, and you're using a bult in fuel tank, check the following.

(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vacuum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.

 

[graco]

Re: 1974 115 evinrude quits after 15 minutes

I diconnected the kill wire (black, yellow)the problem still occurs.If water pump is bad will it over heat and automaticaly shut down?

 

[kenmyfam]

Re: 1974 115 evinrude quits after 15 minutes

I diconnected the kill wire (black, yellow)the problem still occurs.If water pump is bad will it over heat and automaticaly shut down?

Well it will certainly overheat !!!

 

[glassmaster68]

Re: 1974 115 evinrude quits after 15 minutes

first ,you def need to find out if water is pumping through,dont wont to burn it up,,,,if it has been quitting due to overheating,the damage may already be done,,,,i still suspect a fuel problem ,,,,,,,,,if it is pumping water,and you run it till it quits again,check the spark as soon as it dies ,make sure there is fire all around,,,,,,,,,,if you dont have a manual and youre going to try to keep this thing happy with your own skills,i would suggest a manual,,it made my life alot easier,theyre avail here on iboats reasonably priced

 

[ezeke]

Re: 1974 115 evinrude quits after 15 minutes

The problem is probably heat related.

Rebuild your water pump, vernatherm, and water passage deflectors, in that order, and you may well solve the problem.

The complete water pump kit is part #0439140.

Vernatherm is 105 degrees, part #0384719.

Water passage deflectors are #0318357.