Johnson 4 hp motor

[jakondroad]

I am trying to adjust the low speed of this motor and it cuts out when moving the control. High speed seems fine. How do I get it to idle?

 

[itstippy]

Re: Johnson 4 hp motor

Welcome to the iBaots boards!<br />You need to describe the symptoms as precisely as you can. Did it used to idle for you and now it's acting up, or did you just get it and it's never idled right? What year is it? Does it start in the "start" position or do you have to set it to full throttle? Did you just rebuild the carb and you're setting the idle, or was the carb last rebuilt in 1975? Old gas, new gas, old plugs, new plugs, what's the deal?<br />The guys on this board love a challenge, but you gotta give them more to work on than "it won't idle". Clues to help troubleshoot is what they want. Flesh it out a little.

 

[Xcusme]

Re: Johnson 4 hp motor

Welcome to iboats!!<br /><br />Post the model number of your motor, it helps. <br /><br />In the mean time, here are the carb adjustments, thanks to our good friend Joe Reeves. <br /><br />(Carburetor Adjustments - Two Adjustable N/Vs)<br />(J. Reeves)<br /><br />Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.<br /><br />Setting the high and low needle valves properly:<br /><br />NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle va /lve adjustment.<br /><br />(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, wating for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.<br /><br />(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.<br /><br />When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

 

[jakondroad]

Re: Johnson 4 hp motor

To itstippy and xcusme thanks for the help with this motor. Yes I am a Newbe and the information I gave was brief I know. The Motor Model # 4W71D I think indicates it is a 1971. I don't know too much about it's use history except to say it is really clean and with new fuel (mixed 36:1), tank and lines it started up right away and ran well at mid to high RPM. I think I didn't give it time enough to warm before trying to adjust the low speed mixture control. I will give it another test run and try the tips you both gave me and see what happens. I would like to get a repair manual for this motor if one is available. Can you advise me where to get one? <br />Regards, Jim

 

[jakondroad]

Re: Johnson 4 hp motor

Here is some additional information about the 4HP Johnson outboard. Model # 4W71D and Serial # E3364771. It belonged to an older gentleman who was a Grandfather to a friend of my Son. My son used to fish with this man years ago. The man has since passed away, and the friend offered the motor to my Son who in turn gave it to me. The original paint on this motor is hardly scratched or fadded. The motor cover is still polished and very clean. The only thing I had to do was wipe off some dust, and replace the fuel tank complete with new lines. I removed the plugs before I started it, and they appear to be nearly new. The spark tips were dry. I did nothing to the carb prior to the first start attempt. With the choke pulled full on, and the gear selecter in the start position it started after about 3 pulls. I had to play with the choke to keep it running at first, but once it warmed up it ran well at mid to fast RPM. There is no neutral on the gearing, just slow and fast. The low speed mixture control rotates just 360 degrees for the full range of lean to rich. The same is true for the high speed mixture control which is directly below the low speed control. Neither one of them pushes in or out, they just rotate either clockwise or counter-clockwise for adjustment. The water cooling pump in the lower shaft seems to be functioning well while running as there was a lot of water exiting the shaft in the discharge holes. <br /><br />I am semi-familiar with this motor because my Brother had one years ago for his O'Day Daysailer. His version came in a carrycase and the motor shaft had a breakaway pivot so the motor could be neatly tucked into the carrycase. His motor has long ago been sold. While he had it, it performed extreemly well for him as a kicker. <br /><br />I intend to use this motor as a primary power source for my 14' Jon boat on the Cacapon River for fishing. Secondary power will be paddles :>). <br /><br />Have a great day, Jim

 

[itstippy]

Re: Johnson 4 hp motor

Just a great little motor. I saw a string where people voted for their favorie all-time outboard motors and the OMC 3 and 4 horse came out on top for it's depenability and simplicity of design.<br /><br />The high- and low-speed carburator adjustment knobs will only turn but so far because of the knobs themselves. Take the shroud (cover) off and look at the carb and you'll see what I mean. What you do is remove the knobs, adjust the carb needles to perfection, then reattach the knobs with them pointing dead-center in their range. They are there so you can adjust the carb settings SLIGHTLY to help the motor run when it's really cold, returning the knobs to the center settings when it's up to temp.<br /><br />Xcuseme posted the "Joe Reeves Carb Adjustment" for you, which cannot be improved upon. Notice Joe ends with:<br />"When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway."<br /><br />I would not mess with the settings. Return the knobs to dead center position. Run a tank of fresh 87 octane gas mixed 50:01 with good outboard TCW oil trough the motor. If idle does not return nice then you need to tear down the carb, clean it squeeky clean, and install a carb kit. The carb kit's about $20 here on iBoats, or available at NAPA stores. More for a OMC factory kit from a dealer if you want original stuff. The old gas evaporated in the carb, leaving behind a nasty gummy icky horrible smelling mess called "varnish". I suspect this is the case because you say you had to replace the gas tank and hose. I bet you know what sour gas smells like!<br />There are lots of posts on installing the carb kit. Learn to use the SEARCH feature at the top of this page and search the forum for "4HP carb kit" is something similar. It is not hard to do. Clean! Clean! is the mantra. And don't use a pipe wrench or impact hammer on little brass needle valves. Then do the Joe Reeves procedure. If you properly store the thing when it's going to sit for a long time (a year) you won't have to do this ever again. You will absolutely love that little motor!

 

[Paul Moir]

Re: Johnson 4 hp motor

I find with my '72 that the choke never needs to be played with after it starts. Actually it's a real race to get it shut off before the engine stalls from running too rich. That suggests to me that the problem is exactly what itstippy and Xcusme is telling you, that either the idle & high speed mix isn't adjusted correctly or the carburetor is clogged.<br />One thing I do though is run more oil than the factory recommended 50:1. These engines really don't have the innards to support that. See the Oil mix FAQ in the FAQ forum for details. Here's what the inside of your engine looks like:<br /> http://www.shareaproject.com/pages/imageDetail,p,182,i,2537,00.html <br />There are plain bearings on both ends of the connecting rods, the middle and bottom main crank bearings. Also note that there is no bottom crank seal.

 

[jakondroad]

Re: Johnson 4 hp motor

Paul Moir recommends a 50:1 mixture for fuel for my Johnson 4HP. Do all others agree that this mix is good for everyday running? <br /><br />Jim

 

[Pony]

Re: Johnson 4 hp motor

Jim-<br /><br />Paul is saying that it would be a good idea to run more oil in it than the 50:1 factory recommended mix, because of the type of bearings on the inside of that motor need the extra oil. He is a pro at the little jonny/rudes so I would trust his opinion without thinking twice.

 

[jakondroad]

Re: Johnson 4 hp motor

Hi P.O.N.Y. and thanks for the tip on oil to fuel mix ratio. You recommend more than 50:1 because of the engine bearings. How much more is good? Do I just start playing with the mix or what? Don't want to run too much oil do I? I am going to start it today and do some of the mixture adjustment to the carb as suggested and want to be confident about the fuel I'm using.

 

[Vic.S]

I have a 4W75A 1975 Johnson 4HP. It has been sitting for a long time. I got it out to start it up. It took about 15 pulls. I began with new gas/ oil. I started but ran kind of rough. So I added some Sea Foam and ran it for about a hour at various speeds. It seemed to run better. I adjusted the idle low/ high and seemed to run good. But when I shut it off or if it died on me for idling it too low I hd a very hard time restarting it. i would need to choke it adjust the idle a little pull pull pull pull pull. What do you think the problem might be? Is it my points, condenser, coil??? Thanks for helping me. Papa Steve

Most likely after sitting " for a long time" the carb needs cleaning

but

Check the compressions and check that you can get two good strong sparks from the plug leads ( just checking across the plug electrodes is not good enough) If sparks are poor inspect cois and check./clean & reset or replace points .

If sparks and compression are good go for the carb

BUT you should have started a new thread of your own , not resurrected an old one. When the Moderators see this they will close the thread