2001 Johnson 150 fuel delivery problems

[bottomline75]

Greetings...this is my first post. Having a devil of a problem with one of my engines on my Grady. Here's my problem:

I have twin 2001 Johnson 150's model VCXSIG. These are twins, same assembly line, etc. Everything is identical except the gear rotation on the feet. The beautiful thing about twins is that you have a guinea pig to interchange parts until you isolate the problem. I have Northstar fuel sensors. A few days ago, had what I thought was the fuel pump go on the port engine. I came to this conclusion because once the bowls are dry, you have to pump the bulb to keep it running, otherwise it dies. Also, the fuel sensor on the port engine registers 0.00 unless you pump the bulb. Both fuel pumps are VRO2 fuel/oil pumps with the oil intake capped. I premix. I also have two independent fuel tanks on separate lines that I can feed to either or both engines.

Well, I ordered the diaphragm overhaul kit for the pump. Rebuilt it and reinstalled. Engine will still only run so long as I pump the bulb. So, I took the rebuilt pump and put it on the other engine just to check its function. It pumps fuel fine to the strbrd engine, no problems. Put new fuel filter screens (at the intake) on both engines. Put new fuel/water separators on both engines' lines. Checked all lines and cleaned them, no leaks or clogs. Just to double check the bulb on the bad engine, I disconnected the one from the good engine and hooked it up to the bad one and vice versa. Same thing, bad engine still bad, good engine still good. I also disconnected the fuel sensor in case it was clogged, still the same thing. Both tanks' anti-siphon valves are clear, and besides, the good engine pumps fine from either tank. I also checked and cleaned the vapor bowl assembly.

I have also noticed that the bad engine tends to idle at a higher rate than it did before this problem ~ around 1800 on the muffs. I know it is supposed to be slower in the water, but it has always idled around 1200 or so on the muffs prior to this, so it is definitely different. I have not had the boat in the water in almost a year, but run the engines religiously on the muffs once a week.

I am stumped. Anyone have any ideas?

Mike

 

[jonesg]

Re: 2001 Johnson 150 fuel delivery problems

Try the vacuum check valve and its line to the pump.

the pumps are vac powered, no vac no pumpee.

 

[bottomline75]

Re: 2001 Johnson 150 fuel delivery problems

I've pulled both the line and the blue valve on the crankcase. While I haven't tee'd in a gauge, the valve was clear (I still cleaned the small bit of varnish off it) and the hose was clear and normal. I can blow through the valve from both directions once it is off and it operates fine.

 

[bottomline75]

Re: 2001 Johnson 150 fuel delivery problems

Does it sound possible that there is a clog between the pump and the carbs but not in the carbs themselves? I had to do carb kits in all 6 a year ago as several had stuck needles and were overflowing. Fuel flows through as long as I am pumping the bulb. Just a really high idle.

I just ran an external tank directly to the fuel intake on the pump itself. Still no pumpee.

 

[jonesg]

Re: 2001 Johnson 150 fuel delivery problems

That high idle might be the tip you are looking for, if its sucking air it will run lean and lean speeds the engine up, it works like advance.

I think you're on the right track, very possibly something in common with all carbs, a feeder hose near the pump. You can try spraying wd40 around all the couplings, listen for idle change. The problem is if its an air leak usually the idle is wandering all over the place anyway so its hard to detect that way, it might work better spraying water from a windex bottle and see it if bogs down from injesting water.

Also pump bulb up firm( engine not running) and use a flashlight to inspect the hoses closely, look for wet hose or fuel around the pump.

If you installed a new pump, the old hose sometimes doesn't seal very well if it was on the fittings for a long time.

 

[tashasdaddy]

Re: 2001 Johnson 150 fuel delivery problems

AGREE "That high idle might be the tip you are looking for, if its sucking air it will run lean and lean speeds the engine up, it works like advance."

 

[Chris1956]

Re: 2001 Johnson 150 fuel delivery problems

Mike, My '98 Johnny 150 has a vapor pump, which assists in pumping fuel to the OMS pump, as near as I can tell. You might look up your fuel bracket in the Crowleymarine.com parts list to see if you have the same item. It is located above the main fuel strainer.

 

[bottomline75]

Re: 2001 Johnson 150 fuel delivery problems

Trying to pump the bulb with the engine off. There is a definite sucking noise somewhere at the front of the engine with each squeeze. I don't see fuel leaking anywhere, but the bulb will firm up if I pump it fast, then go soft (all with the engine off). Now if I only had someone to pump while I listen/look close up. Boat is closed transom with engines on a 36" setback bracket...

 

[bottomline75]

Re: 2001 Johnson 150 fuel delivery problems

Mike, My '98 Johnny 150 has a vapor pump, which assists in pumping fuel to the OMS pump, as near as I can tell. You might look up your fuel bracket in the Crowleymarine.com parts list to see if you have the same item. It is located above the main fuel strainer.

Same system. Having trouble locating the sucking sound. I pulled off the main fuel strainer (w/a fitting like a white water hose) and the little o ring inside the cap is broken into 4 pieces and fell out when I opened it. Seems like if I cinched it down good it wouldn't matter? Checked the strbd engine just now and it's o-ring was broken too and hanging out of the cap.

Gonna go get a few o-rings and see if that fixes it. My luck, it will be a 2 minute, $.25 part this whole time.... will update in a bit.

 

[bottomline75]

Re: 2001 Johnson 150 fuel delivery problems

Okay. New o-rings. One thing I noticed is that the little round gasket was placed over the cone shaped fuel filter itself and not between the big white nut and the flat part of the end of the fuel filter. I moved it to the inside of the nut so that it mates with the flat part (bottom of the cone) on the fuel filter and reinstalled. Sucking noise was noticeably lower and the engine slowed down a good bit. Now it's leaking a little fuel around the nut itself. Fuel pump still not pumping.

I put some blue rtv gasket sealant between the nut and filter...waiting for it to dry before I pump any fuel through it.

 

[jonesg]

Re: 2001 Johnson 150 fuel delivery problems

A small temp gas tank would help you up close to the carbs while you pump up the bulb, it should stay firm once pumped up until you fire it up.

Uh...oh,

"I can blow through the valve from both directions once it is off and it operates fine."

Its supposed to be a check valve, you should find the vac valve on the other engine only allows air flow in one direction. You might wanna take another look at that, sound slike a problem, cheap fix though.

Meantime, all this fuel you pump to the engine has to be going somewhere, theres an internal leak I think, in one of the components.

 

[bottomline75]

Re: 2001 Johnson 150 fuel delivery problems

May be talking about 2 different things. I've pulled the blue fitting off the engine block that feeds into the pump. I believe it is called the pulse limiter. I can blow air both directions on both of these fittings clearly. Is that right?

 

[jonesg]

Re: 2001 Johnson 150 fuel delivery problems

how can it limit pulse if you can blow thru it from either direction?
If faulty they can do cylinder damage.

 

[kenmyfam]

Re: 2001 Johnson 150 fuel delivery problems

May be talking about 2 different things. I've pulled the blue fitting off the engine block that feeds into the pump. I believe it is called the pulse limiter. I can blow air both directions on both of these fittings clearly. Is that right?

Can you do it on the motor that is working correctly ?? should answer your question.

 

[bottomline75]

Re: 2001 Johnson 150 fuel delivery problems

Took limiters off both engines. Both are clear and I can blow through both from either direction clearly. Should this be happening or maybe they're both stuck open??? Once I sealed off the gas intake, the engine is no longer starved for fuel and is running without going dead. Looks like a bad fuel sensor on that side. The funny thing is, it registers fuel when I pump the bulb, but not when I stop pumping. I can live with a bad sensor as long as the engine runs.