1974 50hp carb questions

[evilgenius877]

my '74 50 hp is running a little rough. it idles real low and even stalls quite frequently. ai WOT it runs smooth but is not really at WOT i know it has more. and spits and sputters in mid range. i noticed that if i spray carb cleaner into the top carb it tries to die out naturally...but if i spray into the bottom the motor picks up power and speed. how do i adjust the carbs to where they should be ?
also.. i noticed the linkage between the two carbs were not right. the lock that holds the two metal shafts togheter was lose so that one of the carbs was not opening fully and it ran great like this. i tightened the screw and now it runs a little like crap as i mentioned above. how do i put these tow carbs in sync and how do i adjust the carbs so that it is running right and better ?

 

[evilgenius877]

Re: 1974 50hp carb questions

also...when i throttle up from about half to full it acelerates and increases power for about five seconds and then falls on its face back to about half throttle but seems to run smooth even though it is not at true WOT.

 

[evilgenius877]

74 50hp johnson carb problem ???

74 50hp johnson carb problem ???

my '74 50 hp johnson is running a little rough. sometimes it idles real low and even stalls and sometimes it idols really high . at WOT it runs smooth but is not really at WOT i know it has more. she spits and sputters when the shifter is in mid range. i noticed that if i spray carb cleaner into the top carb it tries to die out naturally...but if i spray into the bottom the motor picks up power and speed. how do i adjust the carbs to where they should be ?
also.. i noticed the linkage between the two carbs was not tight. the lock that holds the two metal shafts togheter was loose so that one of the carbs was not opening fully ,and it ran great like this. i tightened the screw and now it runs a little like crap as i mentioned above. how do i put these two carbs in sync and how do i adjust the carbs so that it is running right and better ?
also...when i throttle up from about half to full it acelerates and increases power for about five seconds and then falls on its face back to about half throttle but seems to run smooth even though it is not at true WOT but my shifter is maxed out

 

[o/b tech]

Re: 74 50hp johnson carb problem ???

Re: 74 50hp johnson carb problem ???

First it sounds like the carbs need to be taken off and cleaned thoroughly and new carb kits installed. Also make sure that the throttle plates are completely closed when you tighten the screw on the throttle linkage when it is at idle.

 

[o/b tech]

Re: 74 50hp johnson carb problem ???

Re: 74 50hp johnson carb problem ???

It would also be a good idea to do a compression check on the motor. There should be no more than 15 psi difference between cylinders.

 

[5150abf]

Re: 1974 50hp carb questions

Your bottom carb is dirty and your motor is running on one cylinder, if the motor picks up when you spray carb cleaner into it that is most likely your problem.

It can be hard to detect a misfire in a 2 stroke, classic symptoms of a clogged high speed jet.

It is behind the drain screw on the float bowl, pull the drain screw and you will need a really skinny screw driver to get the jet out.

Once it is out run a stranded copper wire through the jet, pull strands back until the wire goes through, run the wire through a couple times and reassemble and see how it runs.

And be careful spraying carb cleaner in the engine, no oil in it, do it too much and you will damage the engine.

 

[tashasdaddy]

Re: 1974 50hp carb questions

you have and adjustable slow speed needle. do this http://forums.iboats.com/showthread.php?t=244013
then when clean and complete, set your low speed needle a 5/8 turn out from soft seated, and then fine tune. do both carbs, not just one.

 

[tashasdaddy]

Re: 74 50hp johnson carb problem ???

Re: 74 50hp johnson carb problem ???

you need an OEM manual, you have several problems. dirty carbs, throttle linkage adjustments. and need to link n sinc. the timing, and carbs.
you have an adjustable low speed needle, is the only difference, in these instructions. http://forums.iboats.com/showthread.php?t=244013

 

[tashasdaddy]

Re: 74 50hp johnson carb problem ???

Re: 74 50hp johnson carb problem ???

double posting waste people time, as i just did. DO NOT double post. i have merged you 2 post. posting volume this time of year is high, you may have to look on one of the previous pages to find your post.

 

[evilgenius877]

Re: 1974 50hp carb questions

and there lies the dilema...i am not trying to A: buy a manual and B: (especially B) tear the carbs down...i just want to know how to adjust them so that my motor runs better smoother or what have you

 

[tashasdaddy]

Re: 1974 50hp carb questions

you have been told what to do to make your motor run. if you don't want to do what is necessary. keep running it and it will probably blow up. if you notice you got the same advice, from everyone.

 

[FillupD]

Re: 1974 50hp carb questions

http://www.iboats.com/mall/partfind...gd_poid=109344&gd_row=49&**********=108850127

Get two kits and take a couple of hours and easily clean up your carbs and put a rebuild kit it them. If you can remove a couple of nuts, remove a hose and take out a couple of screws you could probably fix your motor, or at least it couldn't hurt it any.

 

[evilgenius877]

Re: 1974 50hp carb questions

ok do i need to completely strip it down ? everything out and off of the carb ? the link above is pretty helpful but this will be my first time doing this and i am a little intimidated. is there any tips or tricks? anything i need to watch out for or be careful of? any step by step instructions ?