1964 3HP Johnson Awakening

[Old Motor Fan]

Ok, I'll admit it...I'm stumped.

I have a 1964 3HP Johnson that hasn't run for MANY years. I dumped the tank, cleaned out the varnish, reassembled (with a fuel filter). Replaced both coils, points condensers, spark plugs. Disassembled and cleaned the carb, all ports (except those with compression plugs over them), installed a carb kit with new plastic float, new needle and seat, new bowl gasket, new low-speed needle packings. No high speed needle on this unit. Cleaned the fixed high-speed jet in the bottom of the bowl. Reassembled the carb and now I'm stumped.

I've got great spark. The motor will fire and run for 2-5 seconds and die. It usually will not re-start until I blow out the excess gas in the venturi.

It appears to flood out as I've got fuel bubbling up through the port in the throat of the carb. (New boss gasket around it in the bowl). It seems as if the fuel flow isn't being interrupted by the needle valve. I set the float level as indicated in many threads here, then tried slightly below level. Still flows fuel.

Is there another passage that I'm missing that will allow fuel from the tank into the bowl and up through the center jet? Am I correct in my assumption that the fuel should NOT flow continuously when the motor is not running?

Thanks in advance for the help.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

After much more tinkering, I've come to the conclusion that that extra fuel flow is indeed doing the obvious. It's WAY too rich.

I put the motor in a tank and rigged a way to start it with a drill motor instead of the recoil. At full throttle, it'll start but doesn't rev up completely. It runs for 2-3 minutes, then dies. If I stand by and modulate the fuel shut-off valve I can keep it running longer (revs and lags with mixture).

Am I at a carb replacement point? Or is there something else in the carb that I should check.

 

[F_R]

Re: 1964 3HP Johnson Awakening

Your float valve is leaking. OR the carb vent is plugged up.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

I suspected the float valve may be leaking. New float, needle and seat.

Is the vent the passage that comes out at the intake, upper left as facing the carb inlet (looking at the choke plate)? I've blown it out with both carb cleaner and compressed air. It seems to be open.

How can I get the float valve to stop leaking? Float is adjusted properly with new parts.

 

[Dizz]

Re: 1964 3HP Johnson Awakening

I`ve also been working on a 3hp 59 model.Do you still have the old needle,seat&float to try just for kicks?Mine were original and work fine.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

Yes, I've got them, and if the symptom had started or changed with the new kit, they'd be back in service. It is doing exactly the same thing with the shiny new parts as it did with the old parts. I'm beginning to wonder if there is not a second passage into the bowl that is bypassing the needle valve. I'll be checking into that when I return to the project next weekend.

 

[freddyray21]

Re: 1964 3HP Johnson Awakening

The new float valve should have come with a spring retaining clip to attach the needle valve to the float. You do need it so don't take it off. I have seen where if they were not positioned right they would hang up and not let the needle valve seat.

 

[F_R]

Re: 1964 3HP Johnson Awakening

It seems like there has been a rash of complaints here recently concerning new float valves leaking. Anybody notice that? Reckon there's a connection?

 

[lexkyboater]

Re: 1964 3HP Johnson Awakening

Did you try removing the carb from the float chamber base, hooking up the gas, and hold the float up by hand and verifying that the gas shuts off or still flows? Maybe that will let you see where it's leaking better so you can resolve the problem. I wonder if it's an adjustment problem, and pushing the needle farther up will force the flow to stop? Maybe it's just not quite seating when the float rises to the top? You might even try removing the float and just pushing the needle by hand into the seat to verify it stops fuel flow.

 

[Dizz]

Re: 1964 3HP Johnson Awakening

Is it possible someone before you had carb apart&installed float upside down,and you did same?again,probally not your problem,just an idea.I noticed on my 3hp that the float could go in either way,one way allows valve to seat.could be the bowl won`t go on with the float wrong,don`t know.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

Thanks for the pointers. I'll be back in front of the carb this afternoon.

I will check the positioning of the retaining spring and the float installation. I'm pretty sure it's right-side up, as the little tang that stops it's downward travel is pointing up and engaging to support the float when the needle is open.

I'm going to have to rig a way to take the bowl off and check flow since the fuel inlet is on the side of the bowl and detaches with it. I did take the carb off completely and (with it drained and blown out) blow though the fuel inlet gently. When I roll the carb upside-down and blow, the valve closes and blocks the air. Right-side up the air flows through the carb with what seems to be an appropriate amount of resistance, considering the tiny jet passages.

Something is simply preventing the valve from seating when the bowl is full of fuel. I think when I find that, I'll likely have it solved. I really appreciate the advice, since it's hard to think of something new when you're too close to the project.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

Your float valve is leaking. OR the carb vent is plugged up.

Turns out that I missed one of the ports when cleaning everything out. The bowl vent was indeed plugged with dirt/bug debris or something. I have it back together and the fuel does not continue to flow out of the high-speed jet like it did. The float is seating the needle and all is well on that front.

It starts now and runs a short time, then dies. Seems to be a lack of fuel. I'll open up the carb again and re-check the float level. Maybe a bit too low now.

Thanks everyone for the help, especially F_R. Right on the money.

 

[wbeaton]

Re: 1964 3HP Johnson Awakening

I just installed a new crankshaft in a 1967 and I'm having a similar problem. Runs for a short time then dies if set at "start" or lower, however, it won't idle lower than about mid RPM's. Runs great at high speed. The annoying thing is it ran great before the new crank was installed (no load of course due to the crank splines being worn out). The low speed setting seems to make a big difference on mine even at Higher speed (couldn't get up to WOT since I'm running in a barrel) so I think once I get it out of the can and on the water I will be able to find the sweet spot.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

Well, I've made some progress, I guess.

I was able to get the motor to start and rev up today, but only if I kept the carb inlet partially blocked with my thumb. I would guess this indicates that the float was too low as I was, in effect, choking it by blocking it off. I made an adjustment and got it to run, though not full rpm, with the inlet tube screwed in place. The odd thing is that I had to have the idle jet pretty much closed. Any opening of the jet at all and it would lose rpm and/or die.

Does anyone know if this motor is supposed to have the perforated restrictor between the inlet tube and the carb? It seems the back pressure of having the inlet partially blocked made it run better.

Any other ideas? The float is, at this time, level front to back and side to side, which is where I believe it's supposed to be. No high speed adjustment on this one, only an orifice. I think if I had a high speed needle, she'd be running.

 

[tashasdaddy]

Re: 1964 3HP Johnson Awakening

i think you just found your problem, it has the fixed jet, did you remove it and clean in. blocking the air adds fuel to the mixture, so you are not getting full flow thru the high speed. if it's like the other fixed jets you need a special screwdriver to remove it. i made mine with a screwdriver and my belt sander. the jet is located behind the front drain plug on the bowl, deep down inside.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

Yeah, I've had it out 3 different times. The first time is was partially plugged, but since it's squeaky clean. I've tried 3 different float levels trying to adjust the mix a little, too, and so far no change in the results. When I do get it running, ANY opening of the idle mix and it dies, as if the little extra fuel is too much. I'm going to pull the whole carb again and give it all a good soak. Also going to pull the tank one more time and see if I can get any more crud out of it. It's pretty clean, but I see a little stuff in the in-line filter that I installed on occasion.

I've got one of those hardware store 4-way screwdrivers and the small straight blade fits perfectly, just in case you don't want to build your own.

(Pretty Husky, btw)

 

[tashasdaddy]

Re: 1964 3HP Johnson Awakening

have you seen this: http://forums.iboats.com/showthread.php?t=167352

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

Yes, I have, but thanks for the link just the same.

I've got the entire carb off, disassembled and soaking. The tank is off, drained, and filled (partially) with solvent for soaking purposes. I've also removed some of the hardware after the valve and replaced it with hardware with less bends, bigger holes and a more clear path for the fuel.

I'll be able to get back on it on Tuesday next week. Hopefully I'll make some progress. I got it to idle out of the tank today, but as I set it into the tank running (for cooling water) the load on the prop was enough to cause it to die.

It's improving slowly. I'll get it yet if I'm not careful. It's a sweet little motor and I'd really love to be able to put it back into service after 15+ years of dormancy.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

I put the carb back together, mixed up some fresh gas and tried again.

No real change. It will start and run for a few seconds, then die. If the idle mix is open AT ALL, it will not start. It will not rev up to high rpm in the tank (it has in the past, but doesn't now). It seems to lack power as if set too lean, but adding any additional fuel through the idle ports makes it die, as if it's way too rich. I've tried a level float and tipping the front of the float down some to lean the mixture.

I'm getting real close to draining the tank, putting the lower cowl back on and hanging this one on the wall as an antique. I think, short of changing the carb to one that has both high and low speed mixture screws, this thing just isn't going to run any more.

If anyone has any additional ideas as to what I've got going on here, I'm all ears. Thanks in advance for your advice.

 

[Old Motor Fan]

Re: 1964 3HP Johnson Awakening

VICTORY IS MINE!!!!

It appears that somewhere in the years that the motor laid dormant, some critter or wind or gravity, not sure which, deposited a seed or something that migrated through the carb. It lodged itself under the end of one of the reed valves, thus holding it wide open.

Removed the seed, reassembled, and stuck it back in the tank. It ran immediately. Idles, runs fast, idles some more. No hint of wanting to die out.

THANK YOU to those that offered suggestions and help.

Those that have the similar problem, take off the carb. Remove the single screw that holds the plate immediately behind the carb and remove that plate. On the back is the reed valves. Check them out. May be your problem. It was mine.

Good luck and happy boating!