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Small outboard mechanics...HELP

Posted on 8/25/14 at 6:37 pm
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 6:37 pm
I have a 1989 25 HP Johnson that's giving me issues. Well, AN issue. Cranks fine, idles fair. Typically, when I start it and get going, it runs fine for a minute or two, then bogs down and starts surging...but won't take throttle. I can kill it, and SOMETIMES, it corrects itself.

I suspected it was an air leak, and the other day, I ran it without the cowling, noticed fuel leaking from the line coming out of the fuel pump, right at the connection to the fuel pump (bottom of it going to the carb).

If you're familiar with this motor, there's a short (1 1/2" or so) piece of tubing (fuel line), which connects to a plastic 'L', then to a smaller diameter fuel line that goes to the carb. The leak was where the short tube connects to the bottom of the fuel pump. I remedied this by bypassing the 'L' and running a straight couple to connect the two lines, straight into the bottom of the fuel pump, and using a hose clamp (the kind you tighten up the screw to make it cinch down). It corrected the leak, but it's still doing what it does.

Here's a short video of what it does (sometimes...most of the time, actually) when I give it throttle.

LINK

Any ideas??
This post was edited on 8/25/14 at 6:38 pm
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 6:40 pm to
Also, here's a list of things I've done/had done that may help eliminate some potential answers...

Changed fuel tank/line (replaced with new)
Had carb rebuilt
Had fuel pump replaced
The aforementioned jury rigging of the line out of the fuel pump
Posted by fishfighter
RIP
Member since Apr 2008
40026 posts
Posted on 8/25/14 at 6:49 pm to
Have the fuel tank venting? What kind of spark plugs you are using? NGK only!
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 6:55 pm to
I have tried a vented fuel tank and a non vented one. Funny thing is, as I mentioned, occasionally it runs fine. With that said, it has run fine on either fuel tank. Just not consistently on either.

I'll check the spark plugs, but I wanna say they've been replaced by the knucklehead outboard mechanic. If it was the spark plugs, would it run good some of the time, though?

I used it Thursday, ran like chit in the morning, eventually decided to troll around the marsh. Cranked it up anticipating a short idle trip to another shoreline, but gave it gas just to see. It ran like a top, so I headed on down the bayou about 5 miles to a bay I wanted to go to. Once there, it ran like chit whenever I tried to move around the bay a little, but once I started to head back in, it 'eventually' started running good again, and ran like a top all the way back in. I just don't understand why occasionally it runs great, but most of the time it can't take throttle. It's like it snaps out of it if I keep trying enough, but won't stay like that if I kill it and restart it.
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 6:57 pm to
Also, when it starts that bogging down like in the video, I kill it...start it back up, try again, and repeat that process until it decides to run good. It NEVER corrects itself unless I kill it and start over.
Posted by fishfighter
RIP
Member since Apr 2008
40026 posts
Posted on 8/25/14 at 6:58 pm to
Put it on the hose at night and pull the cover. See if you are getting any spark around the plug wires.
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 6:59 pm to
OK, I'll try it tonight. It's already connected to the hose, as I was trying it today after bypassing that 'L' out of the fuel pump.
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 7:00 pm to
And I appreciate the response, FF!
Posted by fishfighter
RIP
Member since Apr 2008
40026 posts
Posted on 8/25/14 at 7:06 pm to
Also what you can try is start it. If it is running like crap, use a pair of electrical pliers and pull one plug wire to see if any change. No change, plug back and pull the other.

It really sounds more towards that. Maybe a coil is cracked or the plug wire is loose going bad. Look them over real good.
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 7:37 pm to
I cranked it and there is spark at each wire. (In other words, I pulled them one at a time, saw spark on all of them)
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 7:37 pm to
But they are NOT NGK plugs. They are Champion.
Posted by sherrifftaylor
SELP
Member since Jul 2012
878 posts
Posted on 8/25/14 at 8:07 pm to
You may have a piece of trash or a drop of water floating around in the bowl on the carb. May try draining the carb and pump the bulb a few times to flush some gas trough it.
Posted by Spankum
Miss-sippi
Member since Jan 2007
55973 posts
Posted on 8/25/14 at 8:34 pm to
I'm going to say that is an electrical problem...not sure what would cause it, though...
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 9:02 pm to
Wouldn't it be doing it all the time if it was electrical?
Posted by meauxjeaux2
watson
Member since Oct 2007
60283 posts
Posted on 8/25/14 at 9:16 pm to
You either have an electric short or powerpack going bad. If it was fuel related youd be able to duplicate this issue at will.
Posted by BFIV
Virginia
Member since Apr 2012
7706 posts
Posted on 8/25/14 at 9:23 pm to
quote:

You either have an electric short or powerpack going bad


Back when I had my '76 Johnson 55 HP, I had power pack problems less than a year after I bought it new. Factory trained mechanic told me to never try to crank that motor with a weak battery. Said it could damage the power pack. I took him at his word and always kept the starting battery fully charged after he told me that and after I had to replace the power pack.
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 9:29 pm to
Well this one is cranked by the battery hanging off my right shoulder, but yeah...at my age, it's a fairly weak battery.
Posted by meauxjeaux2
watson
Member since Oct 2007
60283 posts
Posted on 8/25/14 at 9:31 pm to
If it was here at my house I'd have it figured out in 30 minutes flat.
Posted by Fishhead
Elmendorf, TX
Member since Jan 2008
12170 posts
Posted on 8/25/14 at 9:39 pm to
Where do you live? I'd pay for someone to actually fix it! I'm sick of paying this guy in Hattiesburg for working on it, but not fixing it.
Posted by meauxjeaux2
watson
Member since Oct 2007
60283 posts
Posted on 8/25/14 at 9:41 pm to
Im north of Denham Springs near BR. Kinda far.
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