'95 Johnson 175

[FreeBeeTony]

Have twin '95 175 Johnsons.
When trolling 1 engine seems to "load-up" and start to sputter and smoke more while in gear. if I shift into neutral the idle rpms shoot to ~2K.......and eventually "clear-out" and will run fine at 4K cruise again.
Any ideas on what this could be?

 

[Faztbullet]

Air leak in fuel line...

 

[FreeBeeTony]

that would cause what appears to be a "flooding" condition at idle in gear?

 

[FreeBeeTony]

Found this brass fitting loose on a hose that is connected to one of the fuel rails going to the carbs.
It was definitely loose......maybe a 1/2 turn. I had to us pliers, couldn't get a wrench on it w/o taking part of the fuel system apart!
I am hoping this loose fitting was the problem I was having with what appeared to be a "flooding" problem.
Didn't do any "testing" yet.......will report back either way.

Thanks for the suggestion!

 

[oldboat1]

That might be it. Would cause lean running, maybe periodically -- consistent with an increase in rpm. If you tuned the carb air mix with that air leak, you may have compensated with a richer setting which could give you a flooding condition. (Guessing here, but think you may have found the problem.)

 

[Faztbullet]

Air leak is before VRO...causes the fuel to aerate and VRO to cycle faster which increase oil ratio. Movtor rev up as lean and smokes more.

 

[dingbat]

Vacuum and fuel leaks surface more and more as the hoses harden with age.

I suggest replacing any OE hoses remaining on the motor and getting rid of any “screw type“ hose clamps used in the system.

The OE ring clamps are a much better solution

 

[FreeBeeTony]

Faztbullet if I'm reading what you wrote correctly, the loose fitting I found would NOT cause my problem as it was AFTER the VRO. correct?

 

[Faztbullet]

Correct as that is fuel pressure out to carbs..might cause bank to run lean but would leave a good rainbow in water and gas smelll if leaking that bad.

 

[FreeBeeTony]

Correct as that is fuel pressure out to carbs..might cause bank to run lean but would leave a good rainbow in water and gas smelll if leaking that bad.

Than that's not my problem,,,,,,,there wasn't a puddle of gas in the bottom of the cowl.
I inspected the fuel lines from the filter/separator to the engine this morning, they look fairly new and in good cond. I just bought this boat last summer.

So you're saying the problem is on the "input" side of the VRO, could it be internal? Maybe try a rebuild kit on it?

 

[FreeBeeTony]

Is it dangerous to operate the engine in this condition? Can this air leak damage the engine?