1989 Johnson 120hp

[Jessejba]

Hey guys, so I've been pouring through the forums and I think I may have found an answer but I'm not 100% sure.

I recently purchased a 1991 Kenner 18 tunnel hull with a johnson 120hp. I went through the boat, replaced the deck and some other things, now I'm at the engine.

what's happening is at idle, it's fine, starts right up no problem. However when I go to put throttle to it, be it in gear or In neutral it begins to idle up, then falls on its face and dies. I've been through all the carbs and cleaned them, I know the fuel pump is working as I started it for a second with the outlet hose off and had fuel flow. My next guess judging from the forums is I either have an air leak, or perhaps its the fuel primer bulb? The man I bought the boat from said he had it in storage for a few years before he sold it. I'm going to find an OEM johnson/evinrude fuel primer bulb as it seems from reading through the forums that the aftermarket ones generally just dont cut it. I was wondering if someone had any advice or something else I could check on to help eliminate any other possible problems or if you think it could in fact be a faulty primer bulb.

 

[interalian]

If it was stored with any fuel in the carbs, they could be filled with junk and would need cleaning. But first, make sure when you move the throttle that the linkages are moving properly - timing advance and carbs.

 

[Jessejba]

I'm assuming the timing advance is the arrow on top of the manifold that holds the carbs? I've already gone through and cleaned all 4 carbs, the was a little bit of gunk in 2 of them. I feel it's also worth noting that when I pulled the drain plugs from the carbs, the bottom 2 carbs had fuel come out while the top 2 had maybe a drop or 2 come out

 

[interalian]

How did you clean them? Full teardown? Did that fuel come out before you started work?

 

[Jessejba]

Yes I took them all completely apart, replaced gaskets and float stop screws. And that was after cleaning them

 

[Jessejba]

Just an update, new fuel lines, bulb, and filter had no change. It ran better the first time I fired it up than it did the rest of my messing around with it. Perhaps its flooded now I'm not sure. What happens now is after 1/4 throttle it just dies all together

 

[interalian]

Will it run for OK some time at 1/4 throttle?

 

[Jessejba]

So, I have a question that may sound kind for silly... I've only got about 1/8th of a tank in it, could the low fuel cause it to have problems? For whatever reason the last time I had it on, I pushed the bulb a bunch trying to get it to be hard, but it felt to me like I was sucking at air a bit. Anyways, that last time it ran perfect, revved all the way up when I throttled it perfectly, and then after I put it back to idle speed it died

 

[Jessejba]

Hmm I guess its gotta be the fuel pump. If I pump the bulb a bunch, itlle run. You can hear it cracking like they do when they've got too much fuel, then then right before either dies it'll go down to a normal idle no pops or anything. Then die suddenly like the fuels been cut off

 

[reelbrothers]

ok, the fitting at the tank has a spring/ball to keep fuel from free flow if a hose fails, my were so gummed up from sitting for years the pump couldn't pull fuel, the bulbs could pull enough to crank but the pump wasn't strong enough, try pumping the bulb constantly after cranking and see if it keeps running, at least you will know it's fuel delivery.

 

[oldboat1]

that 1/8 tank -- is that old fuel, maybe contaminated?

 

[DRCrowe]

I would check your fuel lines and Fuel pump. I know you said your pump was pumping fuel when you tested it for a second. So was mine, but my motor would die after idling for a bit or on acceleration unless I hit the choke. Once I got some RPM's with the choke it would run better. When I pulled my VRO pump apart I found a nice tear in one of the diaphragms. After I rebuilt it the boat runs like new with no issues.

 

[RNSIMPSON]

Jessejba, Did you ever find the solution to this problem. I am going through the same thing with my 98 Evinrude 150HP?