1997 johnson 150 ocean runner

[82welcraft]

I just got a new to me 150 ocean runner . Initially ran fine but had carbs leaking, replaced carb base gaskets and float bowl gaskets . As soon as I did this the fuel pump stopped working. I replaced the fuel pump with 3 different new pumps , new pulse limiter, new fuel line from tank to engine , new primer ball .. engine runs fine when I prime with ball , shortly after it stops pumping gas and dies out . (As soon as the vapor tank runs dry ) . I took the fuel line off the engine with it running and it almost seems as if its pumping gas the wrong direction intermittently.. all cylinders have between 90 and 100 psi cold with throttle plates closed . What could I be missing??? There is a pulse coming from the pulse limiter to the fuel pump , I'm not sure what to do here , any help is very much appreciated!!

 

[dingbat]

I just got a new to me 150 ocean runner . Initially ran fine but had carbs leaking, replaced carb base gaskets and float bowl gaskets . As soon as I did this the fuel pump stopped working. I replaced the fuel pump with 3 different new pumps , new pulse limiter, new fuel line from tank to engine , new primer ball .. engine runs fine when I prime with ball , shortly after it stops pumping gas and dies out . (As soon as the vapor tank runs dry ) . I took the fuel line off the engine with it running and it almost seems as if it's pumping gas the wrong direction intermittently.. all cylinders have between 90 and 100 psi cold with throttle plates closed . What could I be missing??? There is a pulse coming from the pulse limiter to the fuel pump , I'm not sure what to do here , any help is very much appreciated!!

Three bad fuel pumps isn't coincidence.

Time to start at the beginning.

Are you 100% sure of the work you did to the carbs?

Floats set to the right height?

Fuel lines to the carbs get mixed up?

Throughly inspect every component in the fuel delivery system from tank to carbs. Make sure all the arrows are pointing in the right directions.

Fuel hoses on the vacuum side of the fuel pump typically don't leak. Check each and every connection.

Bear in mind, your typical hose clamp is not the best for making leak free connections.

Could possibly save time by removing the fuel hose from the motor side of the primer bulb side and dropping it in a can of premix.

If it works you have a problem between the tank and the primer bulb.

If it doesn't work you have a problem on the motor side.

 

[brodmann]

No idea what a "vapor tank" is. Obviously, the fuel pump sucks gas from the tank and pumps that into the lines going to the carburetors. If you take the fuel line off it will pump some gas out of that opening since there is no resistance in that line when removed. Do you have a fuel/water separator? Has the filter been changed? If not, it's probably clogged. When you say immediately after replacing gaskets, the fuel pump stopped working, how did you determine the fuel pump wasn't working? The fuel pump is a pretty simple part. They don't go bad often, and I've never heard of someone getting a bad one. Your compression is a bit low. That bothers me a bit. Should be around 135. So you're off by about 25% lower than you should be. But I'm curious as to how you diagnosed a fuel pump problem. When replacing the bowl gaskets on the carburetors, did you mess with the floats or needle and seat in the carburetors? Did the floats move freely? On some outboards, when you remove the float bowl, the floats will drop so low that the needle valves can fall out. Any parts left over??? Most fuel pumps have the input and output marked on the hose nipples. Have you paid close attention to that?
Please let me know how you concluded a fuel pump problem.

 

[82welcraft]

Three bad fuel pumps isn't coincidence.

Time to start at the beginning.

Are you 100% sure of the work you did to the carbs?

Floats set to the right height?

Fuel lines to the carbs get mixed up?

Throughly inspect every component in the fuel delivery system from tank to carbs. Make sure all the arrows are pointing in the right directions.

Fuel hoses on the vacuum side of the fuel pump typically don't leak. Check each and every connection.

Bear in mind, your typical hose clamp is not the best for making leak free connections.

Could possibly save time by removing the fuel hose from the motor side of the primer bulb side and dropping it in a can of premix.

If it works you have a problem between the tank and the primer bulb.

If it doesn't work you have a problem on the motor side.

Yes I'm 100% on the work I did . As a mechanic of 20 years I am confident in that . Additionally I've rechecked the carbs twice . I'm certain there are no restrictions from the tank to the engine , everything there has been replaced and the primer ball does not suck itself closed .

Fuel lines to carbs can not be mixed up since they run off of an equalizer fuel rail and only have one line feeding all 3 carbs (per side of the engine)

Vacuum hoses and feed hoses all in respective places .

Fuel flows freely from tank to fuel pump via primer ball and fills vapor Separator tank adequately.
Small pump on vapor tank pumps fuel into carbs as long as the vapor tank is full.
The VRO pump is the one that is not pumping fuel to fill the vapor tank.
Constantly . It does seem to work Sporadically
But nowhere near enough To provide a constant flow and keep the engine running for more than a couple minutes. I agree that 3 fuel pumps. Being bad is almost impossible.. The strange thing is, the problem seemed to have manifested itself. Right after I had the carbs off .To re seal them

All 6 carbs get adequate fuel.
When using the prime ball And seal accordingly when the floats are all full.

 

[flyingscott]

Find the pulse line and reconnect it

 

[82welcraft]

No idea what a "vapor tank" is. Obviously, the fuel pump sucks gas from the tank and pumps that into the lines going to the carburetors. If you take the fuel line off it will pump some gas out of that opening since there is no resistance in that line when removed. Do you have a fuel/water separator? Has the filter been changed? If not, it's probably clogged. When you say immediately after replacing gaskets, the fuel pump stopped working, how did you determine the fuel pump wasn't working? The fuel pump is a pretty simple part. They don't go bad often, and I've never heard of someone getting a bad one. Your compression is a bit low. That bothers me a bit. Should be around 135. So you're off by about 25% lower than you should be. But I'm curious as to how you diagnosed a fuel pump problem. When replacing the bowl gaskets on the carburetors, did you mess with the floats or needle and seat in the carburetors? Did the floats move freely? On some outboards, when you remove the float bowl, the floats will drop so low that the needle valves can fall out. Any parts left over??? Most fuel pumps have the input and output marked on the hose nipples. Have you paid close attention to that?
Please let me know how you concluded a fuel pump problem.

Needle and seats are all working as they should. This engine has a vapor separator tank just above the fuel pump. The fuel passes through a screen which is clean , into a passage beside the vapor tank , then to the suction side of the fuel pump , put of the pump into a vapor separator tank which has another float with a needle and seat , from there its pumped into 2 fuel lines from a smaller fuel pump feeding each side of the engine (3 carbs each ) . The first fuel pump which feeds the float on the vapor tank is the one not working, it runs off of a pulse line on the bottom of the power head which has a pulse limiter (new and clear) if I run the engine with the discharge side of the main fuel pump into a container, it does not produce a flow of fuel , it just spits randomly . There are no vacuum leaks or fuel leaks in the system .. it boggles me that replacing gaskets on the carbs would cause this issue but thats exactly when it started .

 

[82welcraft]

Find the pulse line and reconnect it

Pulse line is connected and clamped . Also ran engine with pulse line off to see if it was pulsing and it does . Not sure if it's strong enough but has a fair amount of pressure

 

[flyingscott]

Sounds like something is hooked up wrong

 

[82welcraft]

Sounds like something is hooked up wrong

That would make sense but I've checked and rechecked everything countless times and everything is hooked up properly. I understand very well how these things work which is why its so baffling. I know 90psi of compression is a bit low but would that cause the pulse to not be strong enough to run the pump ?? If so why was it working before the carb work ? I'm at a loss

 

[flyingscott]

The vapor separator is right above the fuel pump.

 

[82welcraft]

The vapor separator is right above the fuel pump.

Correct

 

[racerone]

There is the electric primer valve ( red lever ) , and that is NOT a pump.----The little pump is a vapor extraction pump.

 

[Faztbullet]

VS housing is leaking air

 

[dingbat]

Yes I'm 100% on the work I did . As a mechanic of 20 years I am confident in that

Ive managed a Service Department for the past 25 years.

Know how many times I've heard I'm 100% confident in this situation?

It ran before you did the work but doesn't now....your missing something

 

[82welcraft]

There is the electric primer valve ( red lever ) , and that is NOT a pump.----The little pump is a vapor extraction pump.

I know that electric primer is not a pump .
Could the vapor extractor pump be causing vapor lock that quickly if it's not working properly?

 

[82welcraft]

Ive managed a Service Department for the past 25 years.

Know how many times I've heard I'm 100% confident in this situation?

It ran before you did the work but doesn't now....your missing something

I agree , I must be missing something, just don't know what that may be .

 

[82welcraft]

VS housing is leaking air

I'll check this after work today.

 

[racerone]

Impossible to get 3 new pumps that are bad.-----Something is hooked up wrong !!

 

[82welcraft]

I've narrowed it down to the vapor separator tank assembly, if I bypass this whole system and run the gas inlet directly to the fuel pump instead of through the vapor tank first, it pumps fuel like a champ ! Do I NEED the vapor tank or will it run and be fine with it bypassed ?

 

[Faztbullet]

Those engines run a LOT of heat under the cowl thus this style fuel system. Either the VS cover is warped, gasket leaking or diaphragm damaged in vapor pump