time to tell the truth....80 johnson 25 hp

[steelshot]

i'm a letter carrier ,about 5 years ago a customer tells me he.s moving.i inquire about old 16 foot grumman in back yard he says i can have it and do i want the motor?i said yes sir !soi i take the motor right away to keep the ups guy or sombody else from scoring it.we go in basement and i see its on its side and the basement floods!sure enough the rope wont budge,i take it home, spray pb blaster remove recoil and use my electric impact driver to go back and forth light trigger of course.it frees up and i put it back together and it runs couple pulls !and idles fine .but when i have in gear just off idle to pick up decoys holding against the wind it misses then sputters right out ,but starts right away,also if i'm holding my place in line at launch same thing sputters dies but restarts no problem.ive adjusted the mixture nobs but no differance,also had carb off real clean like new inside ,did forcing flywheel break a ring or something else?thanks for your time.

 

[bobbyc]

start with a compression test

 

[steelshot]

as soon as i can get some one to hold tester i'll let you know thanks!

 

[steelshot]

i found a tester from 30 years ago uses rubber bladder to friction fit in spark hole has some cracks but i did get readings ,top was with fuel line connected and choke pulled out 106 about same for bottom cyl.maybe 1 lb less used 5 pulls each and tested 3 times johnson long shaft 25 tiller, u25rlcsa, plugs are the recomended champions.they are old though but no erosion.then it fired up and idled in nuetral fine.

 

[qhn]

Above 100lbs is good. No broken ring for sure. Either your spark is week or firing only on 1 cylinder. The other either intermittent or dead. Or, your fuel pump diaphragm is bad. It sounds more like a fuel starvation or a flooded issue, if not the spark.
Good luck.

 

[steelshot]

to be clear it runs at wot fine,and it will idle in neutral at dock no load,till gas is burned.