Fuel Problem

[FreeBeeTony]

Have Twin '95 175 Johnsons.
Have a problem w/ the Starboard engine, stalls out when throttling up. If I let it idle long enough it will die, but start right up when I hit the key, although it does idle rough and at a lower RPM than normal.
Had to limp home on 1 engine today. While coming in I started playing with the "choke" (pushing the key in) while trying to throttle up in gear. By alternating advancing the throttle and pushing the key in I was eventually able to get up on plane and get to full throttle. I was able to repeat this condition multiple times.
I don't think it's the fuel pump because I was able to get to full throttle, and I don't think it's the carbs either.
I have heard of problems with the vapor separator on these engines. Is there a rebuild kit like a carb kit available?

 

[Crosbyman]

vapor separators are usually found on fuel injection engine... unless I am wrong ..again your Johnson 175hp 1995 seems to be a carb engine... on the parts place anyway .. idle passages may be clogged yet HS jet could be fine

experts will chime in

if so.... a carb tune up may be in order have you tried a can of engine cleaner just for trial

may as well post your engine model #..

 

[racerone]

Yes , there is a vapor separator on these carbureted motors !!-----Time to give the fuel system components a good inspection !

 

[Crosbyman]

yep... foiled again i'll stick to oldies

 

[Chris1956]

And why don't you think it is your carbs? I would suspect your carb idle circuit and needle are dirty or out of adjustment. BTW - the idle needle is likely located in the throttle body, not the carb.

Make sure the carb bowls haven't warped. The plastic ones tend to do that.

 

[FreeBeeTony]

And why don't you think it is your carbs? I would suspect your carb idle circuit and needle are dirty or out of adjustment. BTW - the idle needle is likely located in the throttle body, not the carb.

Make sure the carb bowls haven't warped. The plastic ones tend to do that.

I doubt 6 carbs would go bad at once.

 

[FreeBeeTony]

Yes , there is a vapor separator on these carbureted motors !!-----Time to give the fuel system components a good inspection !

Does the description of my problem sound like it may be related to the vapor separator?
I see there is a kit to rebuild the fuel/vapor pump.
Kit,

 

[jhande]

It could have something to do with the vapor separator.

I'm not to accustomed to outboards/boat motors but...
If choking the carbs helped get things up and running a couple of other things come to mind (based on my automotive experience).
Vacuum leak
Dirty ports in the carbs

 

[Chris1956]

Tony, so you think only 1 or 2 carbs would get dirty at once? Let's see same fuel, same time frame, but only dirt in some of the carbs....really?

If the vapor separator cover leaks or the needle is worn, the motor would starve for fuel at high speed, as well. Not what was reported.

 

[FreeBeeTony]

Yes , there is a vapor separator on these carbureted motors !!-----Time to give the fuel system components a good inspection !

Can you describe the function/purpose of the vapor separator?

 

[FreeBeeTony]

I had posted this issue a while back and someone responded saying this was a common problem w/ these engines.........it was suggested to run the engine at a high idle after the engine was running, warm, maybe had something to do w/ "heat soak"? That worked for a while, now seems like what ever was causing the problem is worse.

 

[Crosbyman]

Tony, so you think only 1 or 2 carbs would get dirty at once? Let's see same fuel, same time frame, but only dirt in some of the carbs....really?

If the vapor separator cover leaks or the needle is worn, the motor would starve for fuel at high speed, as well. Not what was reported.

all carbs can get dirty if the fuel and filtering is inadequate

VST cools the fuel on ETECS anyway.... (water is used) and the VST releases any air-vapors, bubbles from the fuel via a top float valve. the vent valveremains open till fuel fills the chamber.
(works like a toilet bowl )
IF the venting pointer valve is stuck shut fuel may have difficulty entering the VST end ultimately the fuel distribution

 

[Chris1956]

Tony, your original description does not match the heat soak issue. Heat soak (if that is what happens), occurs when the motor is run for a while, turned off for 30minutes or so, and restarted. The motor initially runs perfectly at idle and high speed, until turned off and restarted. That is not what you described.

 

[FreeBeeTony]

Correct, I did not mention that the problem occurred after running and being shut off for a while.
So what does this imply? I plan on going down to the boat today an d see how it runs after a cold start. if the problem is there from the cold start I intend on taking the vapor separator apart for inspection

 

[Chris1956]

Great, If the issue is there on initial start up and run, and after you take the vapor separator apart, you can then clean the carbs idle circuits.

 

[Crosbyman]

If anything like VST on modern ETEC be VERY CAREFUL not to snap/break any hose nipples !

 

[FreeBeeTony]

Started the boat this morning and problem is occurring at cold start.
I did take the vapor separator apart and adjusted the float, upon inspecting the needle/seat, the tip of the needle does seem warn, not sure if it's sealing or not. After reassembly I started again, problem still there, may be a little better. I also squirted GumOut into the orifice on the top left of each carb which I think goes to the idle circuit.........
Did a bit more evaluating, if I increase the RPM's at ~2000, after a little bit it starts to stumble, I hit the key for the primer and it recovers. Also seems like it has developed a sneeze, which I know indicates a lean condition.
I even took the boat out in the bay and with the help of the key/primer, I was able to get to full RPM's. May try to adjust the idle mixture a slight bit tomorrow.
Question: at what RPM is the idle circuit not in play anymore?

 

[racerone]

Using the electric primer valve puts fuel directly into the carburetor throat / intake manifold.-----This fuel bypasses the metering circuits in the carburetors.----This strongly suggest the need to inspect carburetors !

 

[FreeBeeTony]

Using the electric primer valve puts fuel directly into the carburetor throat / intake manifold.-----This fuel bypasses the metering circuits in the carburetors.----This strongly suggest the need to inspect carburetors !

Understood.....just don't want to get into it right now. Would it hurt anything to run it like this a few more times until I pull it for the season?

 

[racerone]

You need to understand that IF ( big word ) there is a blockage in a carburetor you might starve one cylinder of gasoline along with the oil !