1962 johnson 28hp likes to buck

[dparker]

i just got this motor and for some reason it likes to buck when under load but when i have it hooked up to my garden hose it runs like a charm......it bucks in low speed and in high speeds and it does it quite often it has some knobs inside the cover and one is for low speed mix and the other is for high speed mix.......i am not sure what this is for could they be what my problem is and also i mixed my fuel at 500ml oil to 5 gallons gas is this right....?

 

[freddyray21]

Re: 1962 johnson 28hp likes to buck

the adjustments are to set the idle (low speed mix) and the wide open (high speed mix) They will run very different under a load than in the driveway. For the low speed I like to run it in until is starts to die then back it out until it smooths out. The high speed is much the same way. You are looking for a smooth running motor at high speed. Be careful adjusting on the boat. They have test wheels you can get to put on in place of a prop to simulate a load in a barrel, but I've never tried one.

 

[dparker]

Re: 1962 johnson 28hp likes to buck

thank you....i will try that.....but i was reading up on fuel mixture and i am very unsure of what i should be running.......i have been running 40/1 as in i mixed 500ml of oil with 5 gallons of gas.....now in anouther post a guy asked about his 1961 10 hp johnson and he was told to mix his gas at 24/1.......so am i running to lean for my 1962 28hp johnson.....and if i am running to lean would this cause the motor to buck

 

[freddyray21]

Re: 1962 johnson 28hp likes to buck

I believe it would be 24:1, but somebody smarter would tell you more. I have a manual at home that would tell me, but not here. Running them lean on oil would not make them buck I would not think, but not good in the long run for the motor.

 

[tashasdaddy]

Re: 1962 johnson 28hp likes to buck

when you say buck, is it a clunk, almost like the motor hit something? here are directions for the carb settings. if this doesn't help, it may be the clutch dog in the lower unit. get back to us on that.
http://forums.iboats.com/showthread.php?t=167352

 

[dparker]

Re: 1962 johnson 28hp likes to buck

yes that is it hahaha a clunk like the motor hit something.........i could not figure out how to describe it and a buck was all that came to mind...thank you i will check out the carb settings and let you all know how it goes

 

[tashasdaddy]

Re: 1962 johnson 28hp likes to buck

it really sounds like the clutch dog is gone. they have really square sharp edged teeth. when they get rounded they jump in and out of gear. it requires a lower unit rebuild, if you can find the parts. it only gets worse.

 

[dparker]

Re: 1962 johnson 28hp likes to buck

alright thank you.....do you think this is a more than likely the problem over bad fuel mixture and a dirty carb plus this morning when i played with it a little i was playing with the high and low speed mixers and it got worse when i played with them......could i simply have water in the carb or the fuel system.....i would like to try that a little more before i try and fix the bottom end.......is there an easy way to set the fuel mixture thanks again everyone for your help

 

[wbeaton]

Re: 1962 johnson 28hp likes to buck

24:1 regular 87 octane gas to TC-W3 outboard oil. The oil ratio won't cause it to "buck".

Just to clarify, it feels/sounds like you've hit something and not like the powerhead of the motor is miss-firing, right? If it seems like its missing then check your coils. You could very well have a bad ignition.

However, if you hear an audible clunk and the motor feels like it engages/disengages then I'm with TD. It could be the clutch dog. Its easy to fix, but the parts can be expensive. A diagram of a 1959 Big Twin lower unit is included in the following link. It should be the same as yours.

www.myfishingpictures.com/showphoto.php?photo=130961

Pull the skeg and check the lobes on the clutch dog (#20). The lobes should be nice and square (90 degrees) along the edges. Here is a picture of a clutch dog from a 1954 Big Twin.

www.myfishingpictures.com/showphoto.php?photo=130256&sort=7&thecat=500&password=

TD gave you a link on how to set your carb. Use it to set your carb before you attack the lower unit. Also check your coils. There is no sense trying to set your carb if you have bad coils.

 

[dparker]

Re: 1962 johnson 28hp likes to buck

ok i will pull it apart this morning and see if the dog is worn......i sure hope not we only have one marina in my town and it could be a pain in the *** to find the parts........if they look fine then i will check my spark and see if that may be causeing the problem......

i dont recall it feeling like it was slipping out of gear it never seemed to loose power but i am very new to this and chances are i am not really sure of what i am looking for lol i was so hopeing that it was more of a fuel mix problem and or a dirty card problem just so it would be a easier fix

thank you again and off to work i go i will let you all know how it goes after i wash my hands hahaha thanks again
DREW

 

[wbeaton]

Re: 1962 johnson 28hp likes to buck

No, no! Check the coils and set the carb first! You need to remove the recoil starter and then the inspection plate from the top of the flywheel and take a look inside. If the coils are cracked or faded they needed to be replaced. Bad coils might work fine when running in a barrel, but will fail under load. Do this BEFORE you open the gearcase.

 

[dparker]

Re: 1962 johnson 28hp likes to buck

oops sorry i did not mention i was gonna do the carb thing and coils first.....the bottom end is forsure not gonna be my first step.....i really dont want to do that at all so i am gonna elimanate everything else first.....the clutch dog idea scares me hahaha....ok outside i go

 

[dparker]

Re: 1962 johnson 28hp likes to buck

ok......i just found out that my impeller is dead......i guess water is suppose to shoot out the hole in the top of the leg and it does not do that......is the impeller hard to change on my 62 johnson and if anyone has a diagram for were to find it that would help also i have no idea on how to change it so........but the bright side of things is i found the part about an hour from were i live so i am off to buy the part haha

 

[wbeaton]

Re: 1962 johnson 28hp likes to buck

The impeller is #36 in the lower unit diagram I posted earlier. Its easy to replace. Your first one might take an hour.

There should be an inspection plate held on by two standard screws located on the exhaust tower above the lower unit (not seen in the diagram). Remove the plate and undo the bottom screw (#8 in the lower unit diagram). Remove the bolts (#6) from the lower unit and pull straight down until the lower unit completely separates from the rest of the motor. Remove the water pump housing which is located over top of the impeller at the base of the drive shaft (#29). Replace the impeller making sure to lock it in place on the drive shaft with the impeller key (#38). Slide the water pump housing over top of the impeller and turn the drive shaft or prop clockwise as you push down on the housing. The impeller should slip right into the housing that way. Installation is the reverse.

 

[dparker]

Re: 1962 johnson 28hp likes to buck

i am sorry....but i am lost.......i think my motor is difrent than the scetch you sent me......do i take the bolts out from the cap below the prop or do i take the bolts out in the next section.......i do not remove the bolts from the leg just below the actual motor

my motor comes apart just below the prop then it comes apart just above the prop and once again all the way up the leg were the leg meet the motor......i know i am a pain in the butt but i dont really want to mess this up so i want to make sure i know what i am doing

 

[wbeaton]

Re: 1962 johnson 28hp likes to buck

Your lower unit should be pretty much identical to the one I posted. Follow the numbers in the sketch with the ones I mentioned.

You need to remove the bolts in the middle section (#6 in the diagram - there should be four of them). Everything below those bolts is the lower unit. The bolts in line with the prop hold the skeg on (#47 - there should be 6-8 of them). If you remove them (#47) you will be in the gearcase.

 

[dparker]

Re: 1962 johnson 28hp likes to buck

ok....thank you so much......i got it done and changed and you were right it took me about 1 hour.....hahaha the hardest part was getting the impeller back in the water pump houseing......now its back to the lake for it and take it for a test run.......

i have changed the impeller and added some iso fuel additive to get rid of any water in the fuel system and changed the oil in the bottom leg so crossing my fingers this will help.....last thing is to play with the fuel adjustments and maybe i will get luckey and the clunk will be gone oh and i also added more oil to my gas to bring the mix up to 24/1

boy have i learned alot in one day from you all thanks and i am sure i will be around for some time hahaha....

 

[dparker]

Re: 1962 johnson 28hp likes to buck

alright in the thread posted for me on setting the high and low speed i am not sure this will work for me......on my motor there are two knobs and they are shaped like triangles and one is for low idle and the other for high idle and both say one way for richer and if you turn the other way it sets it leaner

now in the post link it says to set the idle screw softly and back out x number of times how does it work for mine when they will only turn so far each direction......

 

[tashasdaddy]

Re: 1962 johnson 28hp likes to buck

take the handle off,(screw in center) as it has a stop on it so you can only turn it so far. then just turn the shaft. it works just like the way Joe Reeves says it does. when adjusted put the handles back on.

 

[wbeaton]

Re: 1962 johnson 28hp likes to buck

Its easier to remove the cowl and face plate (springs, etc) so the knob stops don't get in your way. Once you have it set, put everything back together and reposition the knobs (by removing them and reinstalling) so they point to the middle of the lean-rich scale.