64 3hp Johnson won't stay running

[jwh]

Hi All,
Have been working on my 3 hp Johnson and am stumped where to go next. The motor had sat for a number of years. It had no spark on one of the coils so I replaced it with new one. I also replaced the condensors and points. Removed the carb and cleaned and installed carb repair kit. Now has really good spark and it does start but runs for only a minute. Acts like not enough gas but checked bowl and it was full. The only way to keep it running is to keep choke pulled out about half way and then it still might run for a minute or so. Water pump works great too.I have removed the carb several times and checked it and can't find anything. When it runs it sounds great. This is model# jh19a any help would sure be appeciated. Thanks John

 

[sutor623]

Re: 64 3hp Johnson won't stay running

Hi All,
Have been working on my 3 hp Johnson and am stumped where to go next. The motor had sat for a number of years. It had no spark on one of the coils so I replaced it with new one. I also replaced the condensors and points. Removed the carb and cleaned and installed carb repair kit. Now has really good spark and it does start but runs for only a minute. Acts like not enough gas but checked bowl and it was full. The only way to keep it running is to keep choke pulled out about half way and then it still might run for a minute or so. Water pump works great too.I have removed the carb several times and checked it and can't find anything. When it runs it sounds great. This is model# jh19a any help would sure be appeciated. Thanks John

Bad fuel pump. Sucks that they are non-serviceable and cost $90. I had a little bug in mine, and it is near impossible to put these things back together.

 

[sutor623]

Re: 64 3hp Johnson won't stay running

Also, did you soak the carb and spray all the carb jets out with a carb cleaner?

 

[imported_bowfisher]

Re: 64 3hp Johnson won't stay running

Pulling the choke out to keep it running indicates a lean running condition. I would be sure you got the carb thoroughly cleaned and the air screw settings correct. If I am correct this is a gravity fed fuel system??

 

[jwh]

Re: 64 3hp Johnson won't stay running

Hi Pete,
Yes this is a gravity feed and I did soak the carb and spray everything with carb cleaner. There is only one adjustable jet and I have tried all the way from 3/4 turn out from seat to 2 turns going 1/2 turn at a time. I did not realize this thing had a fuel pump, can you tell me where its located. I thought with gravity feed fuel it wouldn't have a fuel pump. Thanks for your help John

 

[Tim Frank]

Re: 64 3hp Johnson won't stay running

Integral tank....gravity feed.....no fuel pump.

If you did not pull the welch plug(s) you need to do that to get at the passages it/they block(s).
What setting are you trying for the low speed needle. Good starting point would be 1-1/2 turns open.

Good link....

http://www.outboard-boat-motor-repa...Johnson 3 HP 1952-1967 Carburetor Tune-UP.htm

 

[sutor623]

Re: 64 3hp Johnson won't stay running

If you did not pull the welch plug(s) you need to do that to get at the passages it/they block(s).What setting are you trying for the low speed needle. Good starting point would be 1-1/2 turns open.

Yup +1

 

[kfa4303]

Re: 64 3hp Johnson won't stay running

Hi Jw. simply spraying everything with carb cleaner won't really do the trick. You'll need to rebuild the carb. It's a simple cheap job. You can get a rebuild kit right here at iboats for about $20. You may also need a new float, if yours stull uses the old original cork float which can/will breakdown over time and clog the tiny passages in the carb. First remove the carb from the motor and fully disassemble it, then soak it and/or clean it thoroughly with aerosol carb cleaner. Until it is absolutely clean the carb will not work properly. Here's alink that can walk you through the job on a car similar to yours.


http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

 

[jwh]

Re: 64 3hp Johnson won't stay running

Hi! Guys,
I am not sure what welch plugs are. Are these the lead plugs located here and there? If so can they be re-used? Will remove carb again and clean thouroughly. I will use kit for carb and buy another float as it is the original. Thankyou for all your help. John

 

[Tim Frank]

Re: 64 3hp Johnson won't stay running

They are small concave discs that are used to cover the cast channels that allow the carb to be properly machined....drills don't go around corners very well....
If you don't remove them it is almost impossible to soak the carb clean in that area....and usually that impacts the slow speed circuit.
I have never been able to remove them without damaging them at least a bit. In fact now i don't even try....just punch (or drill) a hole in them and thread a screw in and yank them.
They are almost all 1/4" or 3/8" and available at many auto and O/b parts stores singly....cost about 20 cents.

 

[imported_bowfisher]

Re: 64 3hp Johnson won't stay running

The welch plug is on top of carb about the size of a dime or so. Made of aluminum and not reusable. Should get one in the rebuild kit.
There are three small holes under it the fuel flows through at idle and intermediate stages that need to be free of blockage.

 

[jwh]

Re: 64 3hp Johnson won't stay running

O.K. I will take a look and see if I can find it. Will get back to you . Thankyou John

 

[jwh]

Re: 64 3hp Johnson won't stay running

Hi! Again guys. Yup right where you said it was. And there is a new one in the kit. Will keep you updated. Again you guys are great. Thankyou John