1995 Evinrude 150 Problems at WOT

[eburr]

Please help-this is keeping me up at night!

My motor normally runs well, but I am getting a steady warning horn when operating at WOT over 15 minutes. Additional symptoms: my new primer ball is sucking flat, and pumping it will normally stop the horn temporarily. The horn also stops when I back it down, or allow motor to rest. There is no anti-siphon valve on my fuel tank. I have a new fuel/water separator. Tank vent is working OK. No fuel line restriction found. I also have a new waterpump and all new seals. Waterpump is working well.

OK, here's the clincher....I have been using really cheap gas (grocery store gas station variety).

Does this sound like bad gas (ethanol/water)? Will adding a gas drier and octane booster help get me through this tank (40 gallons left)? Will switching to a higher octane premium help, especially of a good brand, (like Shell)?

Motor runs great aside from this problem. Help!

 

[72SideWinderSS]

Re: 1995 Evinrude 150 Problems at WOT

If you are sucking the primer bulb flat, you still have a fuel restriction some where in the system.

 

[FISH&RIDE]

Re: 1995 Evinrude 150 Problems at WOT

It could one of two things antisyphon valve located were the gas line connects to the gas tank or tank is not venting. You can use a temperary gas tank to run to see if the condition happens again or remove the gas line before the ball and blow in it, you should not get any resistence. If you do, you can replace the valve or just knock out the check ball inside it out.

 

[eburr]

Re: 1995 Evinrude 150 Problems at WOT

O.K., thanks for these responses, I appreciate your help very much, but please refer to my note above again.

a.) I don't have an anti-siphon valve on my tank, it has a pet-**** instead, and is fully open. There is no ball to knock out.

b.) My tank is venting properly. I have disconnected my fuel line at the primer ball and at various points upstream and blown compressed air backwards into the system, with no noticeable restriction. Air also escapes easily from the tank vent hole.

c.) I have cut my fuel lines down to remove any excess that might require too much suction to draw from

d.) I have changed my primer ball

e.) have also changed the fuel/water filter (ahead of the primer ball)

None of this is working. Bad gas, vapor lock or some type of restriction at the fuel/water separator is all I can figure out right now.

Any other thoughts? I am about to run new fuel lines if this keeps up, unless bad gas can cause these same symptoms.

 

[CatTwentyTwo]

Re: 1995 Evinrude 150 Problems at WOT

Is it possible that you have a screen on your fuel pick up tube in the tank? If you do and there is some crud in the tank, perhaps it it restricting flow at WOT.

 

[eburr]

Re: 1995 Evinrude 150 Problems at WOT

Fuel pick up screen? I hope that is it. I should have dislodged any junk by blowing backwards through the system, so we'll see if that was it.

Is there a possibility that really cheap gas (ethanol-low octane) could be causing this problem? I was a great offender here, and am sure that I was running too high of an ethanol content as a result.

Logically, the problem almost has to be ahead of the primer ball, right? If the ball is going flat, it would mean that the restriction is either in the line, the fuel/water seperator, line to the tank or the pick up on the tank. that is, of course, unless it is just a symptom of bad gas.

I'll get a portable fuel tank to test it if this keeps up

 

[eburr]

Re: 1995 Evinrude 150 Problems at WOT

Fuel pick up screen? I hope that is it. I should have dislodged any junk by blowing backwards through the system, so we'll see if that was it.

Is there a possibility that really cheap gas (ethanol-low octane) could be causing this problem? I was a great offender here, and am sure that I was running too high of an ethanol content as a result.

Logically, the problem almost has to be ahead of the primer ball, right? If the ball is going flat, it would mean that the restriction is either in the line, the fuel/water seperator, line to the tank or the pick up on the tank. that is, of course, unless it is just a symptom of bad gas.

I'll get a portable fuel tank to test it if this keeps up

 

[FISH&RIDE]

Re: 1995 Evinrude 150 Problems at WOT

Fuel line is 3/8? Did the old primer ball work. try switching back to the old one. also the arrow on the primer ball is facing the direction of flow. this is a simple fix but will drive you crazy thing to figure it out.

 

[FISH&RIDE]

Re: 1995 Evinrude 150 Problems at WOT

I don't think its cheap gas or it would run like crap at any speed. you may have to rig a tank with fresh gas aftern the filter to show that the gas,filter and pick-up is not the problem.

 

[72SideWinderSS]

Re: 1995 Evinrude 150 Problems at WOT

I vote for crap in the tank, or last fall not stabilizing your fuel before layup.

I had a similar experience last spring with mine. What mine turned out to be was even though I had stabilized my fuel, I left the boat with about a third of a tank of gas in it. Here in Portland, Or we have 10% ethanol blend year around and high humidity, the ethanol sucked up moisture from the air and when it could no longer absorb any more it fell out of suspension and formed a gelatinous glob of crap in the bottom of the tank. Liked to drove me freakin nuts figuring that one out.

The solution:
Drained the tank, removed the sending unit, stuck the shop vac blowing in the fill from the outside for a day, Rube Goldberg up a hose I could snake around inside of the tank on the shop vac sucking, no debris came out just crap that looked like snot.

Just something to think about.

 

[eburr]

Re: 1995 Evinrude 150 Problems at WOT

Interesting. I have always stabilized my fuel religiously with stabil, even though I have been buying junk gas. I also pulled my sending unit and replaced it last fall, and saw nothing but clean shiny aluminum in my tank. I am now tempted to run this tank out at lower speeds though, and refill with much better fuel next time. Running out means taking a back-up portable tank though, so I can get back in off of lake Erie!

I have not lake tested again since blowing the system out, so maybe I cleaned the pick up screen enough to solve the problem. One can always hope i guess.

 

[72SideWinderSS]

Re: 1995 Evinrude 150 Problems at WOT

You need to use a hand pump through the sending unit opening to remove all of the fuel. If you don't, when you start to vacuum you will go boom. I was told by a fuel engineer you can just leave the goo and wait for it to evaporate. Who in the ell has time for that, not me.

 

[Dhadley]

Re: 1995 Evinrude 150 Problems at WOT

The bulb going flat is because of a physical restriction ahead of the bulb. It could be a kink in the line, a fuel line deteriorating internally, the shut off valve being smaller than 3/8" ID, a 90* fitting being smaller ID, a restrictive water seperator flow and on and on. Could even be a bad valve in the bulb, especially if it's not an OMC or BRP bulb. It's probably not from low octane.

We've had to go so far as to run a different line into the tank thru the fill and right to the motor. Once we know it runs OK, hook things back up one at a time.

Take a look at the shut off valve. If you have any 90* fittings or bulkhead fittings lose them if at all possible.

 

[eburr]

Re: 1995 Evinrude 150 Problems at WOT

All good recommendations. Thanks guys!