1958 Johnson Seahorse Carb Issues???

[jsngendron]

Last year I purchased a beautiful 7-1/2 horse '58 Seahorse, and I ran it all over a couple of lakes all summer with no issues. Also has been running great for the very early portion of this season. However, today I had it running wide open and it very gradually slowed down and stalled. It re-started easily and ran fine until I tried to get it up on a plane again, when it stalled again. It idles perfectly and will run slow up to maybe a little over 1/4 throttle then vibrates some and doesn't seem happy. This kind of came out of nowhere so my first thought is maybe a plugged jet in the carb? This motor of course pre-dates fuel pumps in the Johnson motors, so we know it isn't that. I suppose there could also be sucking air somewhere in the fuel vacuum system (between the motor and remote tank). The quick release fitting is brand new as the old one leaked. Replaced it late last summer. Just looking for thoughts from people who have experienced similar with these oldies. Maybe there is something I haven't thought of.

 

[racerone]

The fuel system is a pressure system.---------Is the waterpump working well ??---------Does spark jump a gap of 1/4" or more on both leads.----------There is a slip clutch below the water pump.----If the spring in it breaks the unit will bind when torque is applied.

 

[jsngendron]

Thanks racerone for the response...the water pump works quite well, so this doesn't seem to be the issue. There is no noticeable loss of pressure at the tank or the fitting at the motor. When run dry (burn all fuel in the bowl), the primer button on the tank fills the bowl quickly and there is no audible leak as there was before I replaced the quick connect fitting with a new one. I was really leaning to this being a carb issue. Does it not sound that way to you?
Will have to test the spark tomorrow.

 

[racerone]

I have one of those motors.--------I can not see or hear your motor.----The trouble shooting is up to you.

 

[jsngendron]

Yeah, I'm here trying to get some help with exactly what I should be trouble shooting. I've gotten a lot of help here in the past. I don't usually get the kind of response you just sent me. If you can't help, don't. Hopefully someone else will.

 

[racerone]

???-------Things to check are in post # 2 mate.

 

[pro-crastinator]

Post #2 data is vital.
That being said, sounds like the bowl is being filled "slowly" - from a fuel line partial clog.
Is the clog in the tank?, fuel line?, carb jet?
Your AD-12 is a gem. I know I treat mine like one.