What am I doing wrong guys?

[Yellowstone]

So, I finished all the work (coils, points, condensers, impeller, carb) on my JW-10 and have everything back together. I started it in the tank and it wants to go and does sometimes for about 5 seconds and putters out. I tried adjusting the low speed needle and it seemed to help but not much. I also was able to slide it up to fast and keep it going but it sounded sick. Is it likely something to do with the carb? I read the Johnson manual and watched several videos on how to seat the needles and then back them out a bit before reassembling and putting back on the motor.

My other thought is it not getting enough spark? New plugs and new ignition system. Thought I had seated the coils right and set the breaker gaps correctly with a feeler gauge But when I torqued the fly wheel down (40 foot pounds per manual), there is a 1/8 gap between wheel and armature plate. Before doing so, I carefully aligned with the drive shaft key and wiggled the wheel down as far as I could by hand. Perhaps it needs to go down further?

Thanks BTW, joining AOMCI, this board and several members have been great in helping out a guy without much previous mechanical experience.

[Randy in Tampa]

Could be both, most likely starving for gas, check to see if the floor is open and close incorrectly by turning it upside down and blowing through the gas passage into the bowl also could be an adjustment on the high speed needle 🤔

Rotary valve Johnson’s Rule!

[aquasonic]

40 Foot-Pounds is at the high end for torque on that motor, so don’t exceed that, or the tapered flywheel keyway may spread and you will be needing another flywheel. The proper torque will seat the flywheel properly as long as the keyway is good. If the keyway is spread, then the flywheel will sit too low and scrape the coil tops, etc.

I guess its time to run some diagnostics. Check for spark on both plugs. Check the points gap again. Check for fuel supply issues in the entire fuel supply system. I believe those tanks have a sintered tank filter that clogs up easily, and especially if old fuel mix was left in there for years. You didn’t mention the high speed needle. What setting are you starting it out at? How about the compression, have you tested it?

I have heard of floats being installed upside down. I haven’t experienced that, but I know it will prevent a motor from running right.

Check the simple basics first: Fuel, Spark, Compression, Air

[frankr]

First things first. What kind of compression does it have? Is it running on two cylinders? Do you have good flow through the sintered filter in the tank? Preliminary setting on carb are 1-1/2 turns on slow speed and 3/4 turn on highs speed. Needs adjusting from there—usually needs to be leaned out.

I’m betting it is running on one cylinder.

Highly unlikely there is anything wrong with flywheel installation.

I had one where the previous owner had installed the pistons backward. But it ran sort of ok, but lacked horsepower.

[The Boat House]

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• This reply was modified 4 years, 7 months ago by The Boat House.

[Yellowstone]

Thanks guys. It was running very good before this. Idled down just before the stop setting smoothly. Problem was, it wasn’t starting the best. Several pulls and a little hard to get going at first. But not like this.One coil was cracked pretty bad and the other not very strong. So I decided to replace both and do the other items as well.

I have not checked compression but will now that I have a gauge to do so. I had disassembled the carb a second time after this issue and when I backed out the low speed needle, some packing did come out. It was really tough to get the packing in there when I cleaned and rebuilt the carb. I put two packing rings in followed by a nylon washer before screwing in the nut. That seemed like the hardest part of working on the carb. Perhaps that could be an issue too. Some of that may be coming out and getting clogged in the carb.

[opposedtwin]

No doubt if some packing came out loose upon needle removal, there’s a very good chance some of it got in and is causing a hickup.

Also regarding the possibility of it running on one cylinder; did you replace plug wires and/or the contacts at the end of the plug wire? (The plug end) If so, it’s important that contact stab through the wire in the CENTER. If it’s off, it could miss the center of the wire entirely. Been there and done that.

Good luck and keep at it!
Scott

[aquasonic]

Something is not making sense regarding the carburetor packing. “It was really tough to get the packing in there when I cleaned and rebuilt the carb”. Once every bit of the old packing is removed, you can install the new packing washers by putting them on the needle, and then screwing in the needle with the packing nut. It should be very easy to install. The hard part, sometimes, is removing the old dried out packing. If packing is coming out in pieces, then that’s a problem.

[Yellowstone]

Thanks. So, I tried just screwing them in there with the needle and they would not go down with it. When I took apart the carb yesterday, I found the best way was to put one wash in at a time, gently but firmly pressing them in with a screwdriver. I used two packing washers followed by the nylon washer. Then I screwed the needle in to where it should be. Slid the nut over it and firmed it in.

I also took a look at the plugs. Tried to gently pull the hood off but one of the contacts ripped out. My plan is to cut that 1/4 inch of wire off and restablish the contact as mentioned above and do the same on the other plug. The plugs are both brand new, installed by the marine service shop when I went there the first week I had it when I had screwed the recoil and couldn’t get it to work right again. I am not going back though. I know I need to figure this stuff out on my own if I want to keep doing it! I appreciate all your help.

[Yellowstone]

So, I got it running great but only for a little bit before one of the spark plugs popped out. I must have stripped the hole when torquing in at the recommended 20 pounds. So, I need to find a parts engine or cylinder head to fix it. Probably the former given the prices I’m seeing. Or, has anyone used one of those spark plug hole repair kits? I’m thinking replacing the head is the better way to go. I can’t believe it. I fired, it up and it ran great for 10-15 second and then that.

For context, I had tested compression, taking the plugs out and grounding the wires. Was very good. Then, I recut the plug wires on both ends for better contact. I reseated both coils on the wires, taking my time, and using my new coil locating ring, made sure they were set properly in relation to the flywheel. Then I used my new timing tool and multimeter to set the timing right. And I finally got the carb to stop leaking. Needless to say I was pumped. And still am. Just one more fix now!

[Author]

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