3HP Johnson Won't Start

[bigk77]

Hi, I have a 1964 3HP Johnson that just won't start for me. I put in new coils and have good spark, and I just rebuilt the carb today. I got it to run for about 10 seconds or so, snd then it sputters out. Any suggestions? I had it running last summer, but only with the choke closed, this year, it won't run for more than 10 seconds at a time. Thanks for the help in advance. Big K

 

[Paul Moir]

Re: 3HP Johnson Won't Start

Bigk, welcome to Iboats!<br /><br />First check that you've got good flow to the carb. Disconnect the fuel line and make sure. There's a fuel filter up inside the tank which may be clogged and cause all sorts of problems.<br />When you rebuilt the carb, did you replace the seal that goes over the main jet? How have you got the high and low speed needle valves adjusted? Did you use a new kit when you rebuilt the carb?

 

[bigk77]

Re: 3HP Johnson Won't Start

Hey Paul thanks for responding. I do have good flow to the carb. I also did replace the seal over the main jet. I adjusted the low speed needle 3/4 turn out. This carb has no high speed needle, just a plug where it would go. I pulled the plug, and plenty of gas is in the bowl. I also did use a new kit when I rebuilt the carb. I am just as stumpped as can be with this one. Any other info I can give for more help? Thanks for the help!

 

[JB]

Re: 3HP Johnson Won't Start

I think your next step is to do the "Outboard wont start" troubleshooting in Engine FAQs, Bigk.<br /><br />Have you checked the fuel tank vent for restriction?<br /><br />It seems that the engine only gets enough fuel to run briefly, then it runs out of fuel.<br /><br />If you spray/squirt fuel into the carb as it tries to quit, does that keep it running? If so, my suspicions are confirmed.<br /><br />Good luck.

 

[bigk77]

Re: 3HP Johnson Won't Start

Well, I went out there this morning to see what I could do, but it won't even pop for me anymore. I don't know what changes in the carb from day to day. but it is really frustrating! I still have good spark, and plenty of gas in the bowl, but it would not go for me. Any clues? Thanks

 

[bigk77]

Re: 3HP Johnson Won't Start

JB you're right, I tried spraying some fuel right into he carb and it started, doing the same thing it was yesterday. Starts for 10 seconds and stops. I tried spraying fuel into the carb while it was running, and that did keep it going just like you said. I took the gas cap off just to make sure that the vent wasn't the problem. I still can't figure out what is wrong. Obviously it is a gas problem, but I don't know what. I really appreciate the help! You guys know what you're talking about!

 

[chris in va]

Re: 3HP Johnson Won't Start

I'm certainly no expert as I just got my 9.9 going, but if you have good spark, fuel is getting to the bowl and you have a fresh rebuild kit, I'm thinking theres something in the carb blocking the passages.<br /><br />One of the issues with mine was the float wasn't at the right level and would allow too much gas into the bowl and flood the engine. I actually had to bend the float plate up a hair to get the correct result.

 

[Paul Moir]

Re: 3HP Johnson Won't Start

I'm inclined to agree with chris. When you rebuilt the carb, did you remove the core plug and clean behind it? Which service manual are you working from? Some have known deficiencies.

 

[Xcusme]

Re: 3HP Johnson Won't Start

Adding more fuel with the spray bottle would not keep the motor running if the carb was flooding. I'll guess you missed something in the carb rebuild. The float should be level with the carb body when the carb is inverted.

 

[rwcreigh1]

Re: 3HP Johnson Won't Start

i would try and do the carb one more time.soak it over night and remove all plugs on the carb.

 

[Fastwin]

Re: 3HP Johnson Won't Start

my 3hp had the same problem. sounds like a blocked jet. does that little fella have a fuel filter?<br />to onblock the jet you get a sewing needle and poke it in the jet and you blow through one of the holes in the bowl i forget which. those 3hp are frustrating i gave up on mine after it caught fire. lol

 

[JB]

Re: 3HP Johnson Won't Start

On those wee tiny carbs it is very common to have a clean jet but a blocked orifice into the carb throat.<br /><br />You can access those orifices by removing the welsh plug or you can take a strand of small wire, put an "L" in the end and go in the carb throat to poke them out.<br /><br />Removing the plug is the better way to do it.

 

[rwcreigh1]

Re: 3HP Johnson Won't Start

to remove those plugs drill a small hole in it then run a screw though the hole them use plyers and grab the screw and pull.good luck

 

[bigk77]

Re: 3HP Johnson Won't Start

Wow! Thanks for all of the suggestions. I pulled the carb off last week and let it soak. I pulled the welch plug, and all of the holes looked unplugged. I then put the carb back together, and still no luck. I then decided to reset the float. I did have it level, but I bent it more twards the bowl and it started to run a bit. So here it how it was set. Float not level..bent twards the bowl, and the low speed needle had to be out 3 full turns and the choke had to be closed. It ran like that for about 10 minutes but then I started playing with the low speed needle, and it died. Any clues on how to make it run with the choke open, and the needle set to a more reasonable position?<br />As a side note, is there anywhere I could purchase a whole new carb or a place where I can send this one to get rebuilt? Again, thanks for all of the suggestions!