Evinrude 150 fuel pump issues?

[tanman34]

Hey guys need some help/advice. I have a 99 ev 150 [J150PXEES]. Havent had it long bought it used from a old guy that had it serviced reg and took very good care of it. The first couple times out no issues. Then the next couple it started giving me issues like the fuel pump was going bad. Each time I came home and found tiny pin holes in the gas lines. So I replaced all the lines,filters and bulb. Been running great on the hose. Took it out ran about a mile fished for a little while then when I went to go again, same thing. Had to pump the bulb all the way back to keep it running. It will get right up on plane and idle as long as you pump it. When its not running you pump it solid and squeeze very hard , no leaks.
So today I took the pump apart and everything looks like new. I also took apart the choke solenoid and repaired it with the kit. It would leak when you turned it and the red plastic had a crack. But it still runs out of gas on the hose.
I am thinking maybe I lost vacuum from the motor to drive the pump. How do you check this? Compression test? I did one when I got the motor and they were within spec.
Anyone got any other ideas?
Thanks.

 

[Chris1956]

That is a very sketchy description. Let's say you have air leaks into the gasoline supply.

Do you have a vapor separator on that motor? How about a vapor pump? The vapor separator cover must seal to avoid pulling air into the gasoline lines. The vapor pump must pump out vapor in the separator to assist the OMS pump.

Is the pulse limiter clean and working properly?

Have you checked the main strainer under the airbox for air leaks?

 

[racerone]

The fuel pump uses PRESSURE to operate and not so much vacuum.-------Test run this motor on a portable fuel tank and hose ( borrowed ) that you know are good.----Compression test numbers are always good to have on hand for future reference.

 

[tanman34]

Thanks for the responses!!
Chris, Yes it has the vapor pump and vapor separator. I was looking at part diagrams last night and noticed it had this. The pump looks similar to the one on my lawn mower and the separator looks like it has a float and probally a needle and seat in there too. I am going to check the pulse limiter today. Can I just unhook the the hose going to it, crank the motor and feel pressure coming out? [not vacuum] The white strainer behind the airbox is new. I rechecked it for tightness and when you squeeze hard on the ball no leaks.
Racerone if I had a tank I would try that but I don't really want to spend the money one just yet.

Gonna do comp test.check pulse limiter today and ill report back today Thanks guys!!

 

[cfauvel]

hmmmm

using the portable tank is a great idea as it could rule out a clog within your tank's system, be it at the anti-siphon valve, tank pickup, fuel filter, etc

The VRO fuel pump uses both pressure and vacuum to operate it. as the piston goes up down it creates pressure and vacuum and the check valves in the VRO directs to which side of the air pump diaphragm gets the vacuum or pressure...I have no idea how much pressure or vacuum that pulse port puts out. I'll defer to racerOne as to which is more prevalent, be it pressure or vacuum...I suspect pressure, as there is a poppet held closed on the air pump diaphragm by a spring and after a certain amount of pressure it pushes the poppet open.
Theoretically you should be able to TEE in a pressure/vacuum gauge on the pulse port to see the needle swing in both directions....but it may ruin the gauge.


BUT you CAn tee into the fuel line inlet a vacuum gauge and see if the fuel side of the pump is drawing enough vacuum...should be about 3-4 inhg.....being a V6 you should have the TEE and a vacuum switch already (which tells you if you have fuel obstruction before the vro).

Curious does your horn chirp when you turn the key to ON?

 

[tanman34]

Just checked the pulse limiter, seems like it is huffin and puffin like it should. After checking this I pulled the fuel pump out and let it hang so I could see fuel coming out. When you first crank it over it squirts gas for 4 to 6 chugs then you can feel something click hard and all fuel flow stop instantly. Pretty sure that is not normal? Gonna take it apart again maybe I overlooked something. It is clicking inside as you crank it more.

Never heard any beeps or horns from this motor. I think there is a special guage that is supposed to be hooked to this motor with lights on it. I think not sure.

 

[racerone]

That pump does not pump continuously.------That may well be NORMAL for that pump !----The reed valves open so it does not pull a lot of vacuum.

 

[cfauvel]

Just checked the pulse limiter, seems like it is huffin and puffin like it should. After checking this I pulled the fuel pump out and let it hang so I could see fuel coming out. When you first crank it over it squirts gas for 4 to 6 chugs then you can feel something click hard and all fuel flow stop instantly. Pretty sure that is not normal? Gonna take it apart again maybe I overlooked something. It is clicking inside as you crank it more.

Never heard any beeps or horns from this motor. I think there is a special guage that is supposed to be hooked to this motor with lights on it. I think not sure.

the clicking sound is the pressure of the air pump overpowering the poppet and releasing the main spring of the air pump, shooting the whole assembly to the opposite direction which is the injection phase for the oil.

I am 90% sure that EVERY OMC motor since 1986 will have a horn (system check or not) that will chirp when you first turn the key to ON. If you are missing the system check gauge I think that is the problem with the horn.....if I recall correctly the System Check gauge is what drives the horn for faults, rather than directly from the TAN leads coming from No-oil, low-oil , temp sensors, and vacuum fuel restriction switch.

Gotta get that horn fixed it will save your engine(well it warn you at least)

Thanks racerone for giving me the reason why there isn't a lot of vacuum from the Pulse Port

 

[tanman34]

Did compression test left side 85,85,80 right 87,92,91.

 

[racerone]

I have a pair of those 150 HP motors.----A 93 and a 97.-----Cosmetically they look the same.-------If I saw 80 PSI I would take the head off for inspection , without hesitating !!

 

[tanman34]

Racerone, why would it stop pumping? The needle and seat? I am testing with it pulled loose from the top so I can see fuel coming out. There is nothing to slow the flow. If you pump the ball gas flows out freely. but wont pump while cranking?

 

[cfauvel]

Racerone, why would it stop pumping? The needle and seat? I am testing with it pulled loose from the top so I can see fuel coming out. There is nothing to slow the flow. If you pump the ball gas flows out freely. but wont pump while cranking?

I believe the pulse port is coming off of bottom left cylinder....so maybe the lack of compression has something to do with the pump's not functioning properly....regardless that 80psi is low.

 

[racerone]

It is crankcase compression that drives the pump.----Not the same as cylinder compression.

 

[tanman34]

Ok so after lots of testing had to make a leap of faith and buy a fuel pump. Got one without the oiler, don't use it anyway. It only cost one arm. And now she is running. Gonna take it down and run it tomorrow to see how it does under load. It seems like there is a check valve on the in and out of the fuel pump.Not sure but I think one of them was malfunctioning.
Thanks for the help and ill report how it runs.

 

[cfauvel]

Ok so after lots of testing had to make a leap of faith and buy a fuel pump. Got one without the oiler, don't use it anyway. It only cost one arm. And now she is running. Gonna take it down and run it tomorrow to see how it does under load. It seems like there is a check valve on the in and out of the fuel pump.Not sure but I think one of them was malfunctioning.
Thanks for the help and ill report how it runs.

There are indeed two check valves in the air pump side. if either or both go out then then pump won't pump.

I got a used one from a forum member who had similar problems and both valves weren't working....it would hold pressure, and hold vacuum, but the air pump diaphragm couldn't move back and forth. on the pressure stroke it would fill both sides of the diaphragm , on the vacuum stroke it would suck from both sides.

The only thing I can think of is that his motor didn't have a pulse limiter and blew out those valves.

 

[cfauvel]

It is crankcase compression that drives the pump.----Not the same as cylinder compression.

right...isn't the pulse port segregated from the other cylinders? so if that cylinder has low compression going towards the head, then it would have low compression as it comes down towards the crankcase?

I have to defer to you on that as I've never taken a block apart.

 

[racerone]

That motor like any other 2 stroke has a separate crankcase for every cylinder.------Crankcase compression can be low for various reasons.------Crankcase compression can be low even if cylinder compression is correct !

 

[cfauvel]

That motor like any other 2 stroke has a separate crankcase for every cylinder.------Crankcase compression can be low for various reasons.------Crankcase compression can be low even if cylinder compression is correct !

oh right.. like if you have a bad lower crankcase seal.....gotcha

 

[racerone]

Or a broken / worn out seal ring on the crankshaft ( 8 or 9 of them on a V-6 ) metal rings that look like piston rings.----Or a reed valve broken ( rare ) or reed valve stuck open with say a seagull feather.