1968 9.5 hp Johnson won't stay running.

[remy308w]

I bought a 1968 9.5 HP Johnson outboard a few years back and it's always done great until this past summer. It won't idle for long when I can get it started, on the water it will run with the throttle wide open but only for a few hundred yards before it starts to jerk and cut out. It seems to do better with the hood off and will run if I spray starter fluid into the carburetor every 20 seconds or so . The carburetor seemed to have fuel leaking from it but not from a central location. It looks wet from top to bottom. I bought a Seloc repair manual it helps for repairs and maintenance, but doesn't have a great trouble shooting section. I've cleaned the carburetor, replaced the plugs, wires, fuel pump, water pump, fuel tank, fuel line, and fittings. The plugs fire and the carburetor gets fuel. I have not checked the compression. I'm new to the world of outboards so I hope I gave you enough to go on. Thank you.

 

[ENSIGN]

Re: 1968 9.5 hp Johnson won't stay running.

The first thing to do is throw the starting fluid away,you'll ruin the motor.put some pre-mix in a spray bottle and use that instead.Sounds like you missed something in the carb,soak it overnight in carb cleaner and blow all of the passages out with a air hose.USE CLEAN GAS

 

[ezeke]

Re: 1968 9.5 hp Johnson won't stay running.

"on the water it will run with the throttle wide open but only for a few hundred yards before it starts to jerk and cut out"

Multiple possibilities here, but most likely that you are running out of fuel in the float bowl from a stuck float valve needle. When you rebuild your carburetor with a OEM kit, be sure to connect the new needle to the float with the clip.

 

[remy308w]

Re: 1968 9.5 hp Johnson won't stay running.

Thanks for the advice! I will get to it as soon as I can. Please keep the advice coming, I need all the help I can get.

 

[Sargent Skiff]

Re: 1968 9.5 hp Johnson won't stay running.

I can only give you half an answer here, but maybe someone else will pipe in. Running better with the hood off is a common symptom with these motors and has a very specific cause. I almost think it's due to an exhaust leak between the power head and the lower unit.
If one of the experts doesn't join in soon, do a search on this forum and I bet you'll find it.

 

[ezeke]

Re: 1968 9.5 hp Johnson won't stay running.

Exhaust leaks are common with the 9.5 because of multiple possible entry points:

The hose for the exhaust relief is easy to check; [see 1, thumbnail]

The large exhaust housing seal between the inner exhaust and the lower cover must be tight; [see 2, thumbnail]

The driveshaft seal on top of the waterpump is often missing entirely;

The shift rod boot can leak or may be torn.

Even if all of the seals are good, the motor may still inhale exhaust when running in a bucket.

 

[remy308w]

Re: 1968 9.5 hp Johnson won't stay running.

Thanks for the new info and pics, they really help. I wish my motor had been maintained over it's lifetime as well the one in the pic. Mine has excessive grease and dirt around the shift linkage area. How should I go about cleaning the motor up?

 

["G"]

Re: 1968 9.5 hp Johnson won't stay running.

Thanks for the advice! I will get to it as soon as I can. Please keep the advice coming, I need all the help I can get.

The best advise that can be given is this... ALWAYS do a compression check. So many problems are found and or diverted when you do that first.

 

[remy308w]

Re: 1968 9.5 hp Johnson won't stay running.

Ok, I've cleaned and rebuilt the carburetor, checked the compression (which was even), installed new points and condensers with correct gap, and syncronized the throttle and fuel. After several attempts I finally got it to start but, yet again it would only run at full throttle and only for a minute. I know it's getting gas and fire. I retraced everything a few times but after several tries, a sore back , and three pull ropes i'm at my wits end. What am I missing?

 

[ezeke]

Re: 1968 9.5 hp Johnson won't stay running.

With the motor in neutral, turn the tiller arm as far as it will go counterclockwise against the neutral stop and then try to start it.

When you worked on the points, did you check the position of the coils to be sure they are correctly aligned with the flywheel?