Poor running '75 15HP

[Joe Dirt]

Re: Poor running '75 15HP

Thanks for the help everyone- I'm off to try to fix 'er. I love my little Johnson 3HP, but she was crying last night trying to push my boat around...

 

[Xcusme]

Re: Poor running '75 15HP

One last suggestion:

Be SURE each of the under flywheel coils are properly 'indexed' on their mounting bases. That coil looks like it shows signs of heating from contact with the fly wheel.

Here's hows to check the mounting...make sure surface A is flush with surface B on both of the coils mounting bases.

 

[Joe Dirt]

Re: Poor running '75 15HP

So should they line up exactly one surface face to the other both front to back and side to side? I noticed mine were a bit out of whack on there

I got her running- thank youuuuuuu! It was the points adjustment. I have to choke out a little bit, more as she warmed up to keep her running at high idle, but I can't open her up in gear to blow some stuff out obviously, or I'd blow all of the water out of my barrel as it went sailing across the parking lot. I may need to decarbon now after running an hour or so on one cylinder last time I was out to get her running good again? Or is there another procedure I need to do now?

 

[Xcusme]

Re: Poor running '75 15HP

Each coil should have 2, one on each front side of coil , like the picture shows. My pic shows the left side of the coil, there's another on the right side of the coil. The dark areas of the coils looks like they were getting hot from friction from contact with the spinning flywheel, which isn't good.

Don't rev her too high in a barrel, either in gear OR neutral. Carb mixture adjustments are best done on the lake. A decarb can't hurt, the procedure is outlined here on various posts, do a search or perhaps look in the FAQ's.

If you can't get a smooth low idle without the choke, it points to a clogged carb in the low speed idle circuit. A carb rebuild should get things running good.

Edit:
Just re-read your last post....you'll want to move the coil forward or back until both surfaces match. If the coils are mounted too far out (closer to the flywheel) you run the risk of them contacting the flywheel. Too far back and the coil won't develop full voltage.

Be sure to torque the flywheel nut to specs or it may shear the flywheel key when you start/run it.

 

[Joe Dirt]

Re: Poor running '75 15HP

I think I have a bum tank or line- I choke to start, (even when warm) I need to keep the choke out about 3/4" to keep her running, If I push it in, it stalls. If I pull out further, it stalls. It's not just idle- it won't even run- at high idle, it'll stall out if the choke is in, so my guess is that it's not getting fuel, unless the fuel pump went kaput, but that was replaced a couple of years ago just prior to me buying the boat, and has maybe 5 hours on it. I pumped up the hose off the motor and pushed in the ball in the fuel connector- and nothing came out. I've never liked this hose, or tank. I was goig to replace them anyway, so I'm going to grab one and try it.

I did a carb rebuild a couple of weeks ago, so all is new in there, and should be clean unless running it the way I did foulded something up in there, but the carb is easy to pull, so I'll probably pull it out and clean it up anyway.

I'll be pullin ghte flywheel off again to align my coils when I get her rolled back in the shade- man it's hot out there!

 

[Joe Dirt]

Re: Poor running '75 15HP

Well she's idling nicely, aside form spending some time fine tuning the idle adjustment once I get out on the lake and have some time to run around. I put a new fuel line on the tank and she idles fine, so I must have had a good air leak in the old line.

Thanks for all the help, everyone!

Fish on!