johnson 33hp wont run good at high speed?

[matt9923]

I have a 1970 Johnson 33hp. I have it running good at low speed but when you give it throttle to go onto high speed it cuts out and doesn't seem to get the right air fuel mixture. I can get it up playing with the needle with my bro driving but it still runs rough? Didn't do carb rebuild and am going to but what else could it be. Do i have to hook that solenoid up to a wire? Ir is that for a ground. What does that solenoid do?
could it be carb, fuel lines, carb seals, gas pump? Im thinking of redoing all these this winter but may have to sooner?
Thanks Matt
Has new gas and gas pump line. and cleaned carb and fuel pump. It will run all day on low throttle but not at high speed.

 

[david_r]

Re: johnson 33hp wont run good at high speed?

carb adjust

http://forums.iboats.com/showthread.php?t=167352

you are better off to do a rebuild when you disassemble a carb

does it help if you pump the primer bulb during prob?

 

[matt9923]

Re: johnson 33hp wont run good at high speed?

carb adjust

http://forums.iboats.com/showthread.php?t=167352

you are better off to do a rebuild when you disassemble a carb

does it help if you pump the primer bulb during prob?

I adjusted everything, didn't try pumping the bulb maby will try again later. I can get it going on the needle rough but after letting throttle off and hitting it again it does it again.
Thanks

 

[tashasdaddy]

Re: johnson 33hp wont run good at high speed?

you probably have a dirty carb, and misadjusted. use the above link, and this one, you carb is similar, with adjustable jets, but the principle applies.
http://forums.iboats.com/showthread.php?t=244013

 

[matt9923]

Re: johnson 33hp wont run good at high speed?

you probably have a dirty carb, and misadjusted. use the above link, and this one, you carb is similar, with adjustable jets, but the principle applies.
http://forums.iboats.com/showthread.php?t=244013

It was clean endless something was in my gas. It was running good yesterday but then the gears were off so it wasn't going into forward. Fixed that. Then today it worked for a little then dies. About after it warmed up it did it. But it stays running at slower speed.

 

[jay_merrill]

Re: johnson 33hp wont run good at high speed?

The solenoid is an electric choke solenoid.

I suggest that you reseat your low and high speed needle valves, by screwing them in until they bottom out. Do this gently - tightening them too hard can change the shape of the tips. Once this has been done, back the low speed valve (top) out 1-1/4 turns and the high speed valve 3/8ths of a turn. Go run the boat again with your brother and try to power up to WOT. Adjust the high speed valve inwards in an attempt to find the peak lean point. This is done by turning it it until the rpm peaks, and then begins to decrease - once it does, back the valve out again until you return to peak rpm.

If this doesn't work, you have other problems. It could be a dirty carb, a need to sync the carb with the armature plate, ignition problems, etc. The best thing you could do if this comes to pass, is to buy a OEM service manual. It will contain troubleshooting information and detailed steps for fixing various problems. Manuals are available here at iboats, and via other sources.

 

[tmcalavy]

Re: johnson 33hp wont run good at high speed?

Yup, if your carb is clean and the ignition system is firing do the link n synch procedure for your outboard.

 

[1970kayhydro]

Re: johnson 33hp wont run good at high speed?

I have a 71 40hp johnson that was doing the same thing sounds like. I did a carb rebuild, decarb and some new plugs and it helped loads. Mine would hardly run more than half throttle, now it really gets up and goes. The carb kit was 35$ plugs 3$ and can of sea foam 8$ well worth the 46$! Good luck.

 

[matt9923]

Re: johnson 33hp wont run good at high speed?

I have a manual. It idles only at about 1/2 out? ill try 1 1/4 and 3/8 tomorrow. What is link and sink? and how do you use sea foam?
Thanks Matt
It has new coils, points/condenser, plug wires, plug, kill switch harness.
cleaned carb cleaned fuel pump.

 

[david_r]

Re: johnson 33hp wont run good at high speed?

decarb

http://forums.iboats.com/showthread.php?t=158076

it did wonders for mine

 

[jay_merrill]

Re: johnson 33hp wont run good at high speed?

On your motor, the procedure really isn't a "link & sync" in the same sense as the multi carb motors. There is, however, a procedure to sync the carb butterfly with the spark advance. My 33hp manual is for a 1968 model, but it is probably the same, or nearly the same as yours - look on page 3-9 for the section title "CARBURETOR ADJUSTMENTS."

 

[1970kayhydro]

Re: johnson 33hp wont run good at high speed?

There is a rod that opens the main "butterfly" or flap in the carb that is on the right side ot the motor. You want it closed at no throttle and all the way open at WOT. You don't need to have the motor runing to check it, just look in the carb with the choke off and you will see the other one. It just needs to be closed and all the way open when the throttle is all the way up. There is a set screw in a stoper that moves just in front of the fuel pump and up a bit.