1988 Johnson 120 - Intermitent running rough / primmer bulb soft

[Fishaholic]

CJ120TLCCA - C 823799#

It started out really hard to start. Had to choke it way more than usual. Then its idleing rough and dies easily. Nail the throttle and it stumbles and then takes off, stumbles alittle more then jumps on plane and runs fine. Runs great up on plane, till you start to turn or just back off the throttle, then it starts missing again. Almost like its only running on 2 or 3 cyls. I thought to check the primmer bulb while it was running rough and it was very soft. A few sqeezes and the bulb is hard again and she's running strong.

So do I have a leaky fuel line somewhere? How do I get'er straight without spending too much?

I tried to search this topic but something isn't working right with the searches.

Thanks for reading my post

[RUSTY63]

Start with the basics, check compression, check ignition and then check the fuel system, could be a carb flooding.

[Fishaholic]

Thanks Rusty. I decided to change the fuel primmer bulb, it was old and wouldn't stay hard.

Took her to the lake and she ran like a sewing machine. Then I go to load it up and it starts running really rough again. I could bearly keep it running enough to get it on the trailer. Its not just a slow idle but more like one cyl. isn't firing or somethin. Mind you, this is only seconds after a 2 mile run without even a hiccup.

I would let the professionals look at it if I could

I'm still leaning toward bubbles in the fuel? or maybe the VRO? I have never done anything to the carbs. Maybe they are feeling neglected?

HHHHEEEEEEEEELLLLLPPPPPPPPP,.............PLLLLEEEE EEEEEEEEEEEEEEEEEEEEAAASSSEE

[ChampioNman]

3 hours to Hellhole TN or 3 hours to Armpit SC. Pull your plugs and check the color of them.

[Fishaholic]

Plugs looked ok except for the driver's side bottom plug was kinda black (that one was 127psi). The compression test was 127,119,132,129. Using Champion QL77JC4.

[RUSTY63]

Black and dry or black and wet?

[302w]

Do you pre-mix your gas? I had a very similar thing happen to my 115 johnson and it ended up needing new needles and seats.

[Fishaholic]

Black and wet.


Yeah, gas is pre-mixed.

[RUSTY63]

Miss fire, bad reed?
Just thoughts.

[Fishaholic]

You could fill a thimble with my experience with 2 stroke motors, but here goes. The reeds are somewhere near the intake and they serve some important purpose right?

[RUSTY63]

With the motor off, remove the air box, open the throttle plates and look inside, you may need some light, you are looking for a missing reed.

I doubt this is your problem but as I posted...Just Thoughts.

[dhagemeier]

The problem you are having is probably a fuel restricton between primer bulb and pickup tube in tank. Try to remove pickup tube by unscrewing square aluminum fiting, Next ; aluminum tube-inspect inside for cone stainless screen
plastic tube-remove screen from bottom.

David 703-517-2626.

[RUSTY63]

I would think if this were the problem he would have a run out of gas at high speed issue.

[Fishaholic]

Just as you suspected Rusty63, the reeds are all intact. Although there was a pool of oil sitting in the bottom of the air silencer. 3 or 4 capfulls I guess.

The fuel lines under the silencer are very wet with oil/fuel. MAybe one of those little dudes is leaking?


Modified by Fishaholic at 3:14 PM 7/6/2007

[Fishaholic]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dhagemeier &raquo;</TD></TR><TR><TD CLASS="quote">The problem you are having is probably a fuel restricton between primer bulb and pickup tube in tank. Try to remove pickup tube by unscrewing square aluminum fiting, Next ; aluminum tube-inspect inside for cone stainless screen
plastic tube-remove screen from bottom.

David 703-517-2626.</TD></TR></TABLE>

I started a siphon at the bulb ( needed gas for weedeater) and the gas flowed freely.

[dhagemeier]

Just a final comment on my previous response. A marginal fuel restriction would would result in a loss of tope end power on inboards or most 4 strokes. a marginal fuel restriction on 2strokes results the motor running leaner with a little more top end, opposite to most common thinking. Again David at 703- 517-2626 to help clarify and help with your problem/situation.

[Fishaholic]

Went fishing last night. Motor ran like crap, until I got my partner to go back and pump the fuel bulb. As long as he kept the bulb full of fuel it ran great.

I am going to dig deeper into the fuel feed from the tank. Thanks David and Rusty63.

[Fishaholic]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dhagemeier &raquo;</TD></TR><TR><TD CLASS="quote">The problem you are having is probably a fuel restricton between primer bulb and pickup tube in tank. Try to remove pickup tube by unscrewing square aluminum fiting, Next ; aluminum tube-inspect inside for cone stainless screen
plastic tube-remove screen from bottom.

David 703-517-2626.</TD></TR></TABLE>

BINGO!!! Just took the pickup tube out and the cone screen was seriously clogged. Thanks again David!

[Bassmeister]

Glad ya got the fix Chip!! Good call David!!

[Fishaholic]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fishaholic &raquo;</TD></TR><TR><TD CLASS="quote">

BINGO!!! Just took the pickup tube out and the cone screen was seriously clogged. Thanks again David!</TD></TR></TABLE>

That screen was at least 90% clogged. I thought for sure that was the source of my problem. Well it wasn't. It still has the exact same symptoms I'm stumpped. What else can cause the bulb to go soft and starve the motor for fuel. The VRO?