1995 johnson 50 2 stroke problem wot

[sean408]

hey everyone

so in have a 1995 johnson 50 2 stroke outboard pushing a 1977 signa 17 tri bow now my problem is that after i rebuilt the carbs now the highest rpms i can get is 3000 before i rebuilt them it would get up to 4500 to 5000 rpms . i just cant seem to find the issue here is a list of things i have done so far


rebuilt carbs
replaced thermostat
new ignition coil
new fuel pump
new fuel filter
new spark plugs
new powerpack but returned since no chamge happened
currenty in process of replacing the gear oil
new prop 12.5×15
new impeller
comp test cyl 1 120 cyl 2 120



any advice would help out alot really dont want to take it to a shop

 

[jakedaawg]

Check for spark on both cylinders.

check that linkage is properly hooked up.

verify that throttle butterflies go to to horizontal at full throttle.

verify that two piece rollers at throttle and timing cam are complete (outer skin still there)

verify that arrow on bulb points toward motor.

verify that fuel lines are not pinched or kinked. Especially under VRO and at the inline filter.

Are you confident that you got the carbs back together correctly? Orifice cleaned and installed properly? Washer under the seat if applicable?

tilt motor a few degrees, squeeze bulb til firm. Continue squeezing gently. Are you able to keep squeezing? See fuel coming out the front of a carb?

If it ran at 5k what led you to rebuild carbs? What was the original symptom? Was that resolved?

 

[sean408]

Check for spark on both cylinders.

check that linkage is properly hooked up.

verify that throttle butterflies go to to horizontal at full throttle.

verify that two piece rollers at throttle and timing cam are complete (outer skin still there)

verify that arrow on bulb points toward motor.

verify that fuel lines are not pinched or kinked. Especially under VRO and at the inline filter.

Are you confident that you got the carbs back together correctly? Orifice cleaned and installed properly? Washer under the seat if applicable?

tilt motor a few degrees, squeeze bulb til firm. Continue squeezing gently. Are you able to keep squeezing? See fuel coming out the front of a carb?

If it ran at 5k what led you to rebuild carbs? What was the original symptom? Was that resolved?

thanks for the reply so i rebuilt the carbs because when i would go any speed the motor would surge and rpms would go down for about 2 seconds and then go back up i checked throddle plates and they open all the way both at the same time together i did an ohm test on the timer base and the stator both check out ok according to specs from manual cant find an arrow if there is one on the bulb and for the vro that has been taken out and i premix 50.1 also have stablizer in it to. and the timing cam and rollers are complete . and i have spark on both cylinders i know that for sure because i got stuck on the river but carry an extra coil

 

[oldboat1]

Carbs have idle mix needles, so I would start with those. They need to be set at the mid point between too rich (c.clockwise) causing rolling or stumbling, or too lean (clockwise) causing stalling or lean sneeze backfire. The nozzle gaskets have to be in place for the carbs to feed properly, and the high speed jets at the bottom front behind the plugs have to be squeaky clean.

[Edit. I would use Champion QL78C or QL78YC gapped at .030. Measure spark to test ignition strength, using an adjustable open air tester.]

 

[sean408]

thanks i will check the gap today also the new plugs i have are the ones mentioned and ill check needles this weekend manual says starting point in 3 turns from slighly seated but that seems a little high to me

 

[racerone]

Are the nozzle gaskets installed ?-----What did you find in the carburetors when you " rebuilt " them ?----There is not much that can go wrong with them !-----What other trouble shooting has been done , if any ?

 

[sean408]

yes nozzle gaskets are in floats are adjusted per manual jets are clean i let them soak in carb cleaner for a day i actually rebuilt them twice bec i forgot to adjust the floats when i rebuilt them there were stains in the float bowls dirty etc. ive checked timing checked stator timing base with an ohm meter replaced ignition coil powerpack ran a seafoam treatment through the motor with a gallon of gas and a can of seafoam it might be that i did not adjust carbs correctly with the correct fuel ratio the thing that is kinda confusing is there is no air screws like a regular carb or it that only on 4 stroke carbs im going to fill a garbage can up and put the boat trailer on ramps and see if i can get the carbs adjusted better and see what happens on sunday

 

[oldboat1]

Helpful if you would post a model number.

 

[sean408]

model number ? are you refering to the model of the engine ?

model number for the motor is J50TLEOD

 

[oldboat1]

http://ww2.iboats.com/Carburetor-All...iew_id.1534362

#18 is the idle air mix needle. Don't confuse the air mix with the fuel ratio (gas to 2-cycle oil), or the throttle idle adjustment.

 

[sean408]

yes i under stand that but what is confusing me is that is #18 control fuel and air of just fuel.

 

[oldboat1]

controls air to ideally provide a 14.7:1 air/fuel mix (ratio) during idle.

 

[lindy46]

I would set the idle screws to about 2-1/4 turns out, but they shouldn't affect high speed operation. What prop was on it before?

 

[sean408]

sorry for the late reply i took it out to the delta sunday and i got the carbs perfect runs very smooth but cstill can not get it up to the 4500 to 5000 point . not im thinking it could be the prop i went from a 12.5x12 to a 12.5x15 to get higher top speed what do you think the 12.5x12 was slightly damaged so thats why i changed it. but do you think that is enough change to bring those rpm that low on wot

 

[lindy46]

Switch back to the old prop and see what happens.

 

[sean408]

ok will do im going out this sunday and i will find out. result to be determined

 

[sean408]

so took it out on sunday and put the 12.5×12 prop back on and rpms went up from 3000 to about 3300 rpms . so preety much no change. now im flustered to what could be the problem. at this point ill try anything

 

[racerone]

Checked the flywheel key ?-----Checked the reed valves ?------What position is the red lever in ?------Remove airbox.-----Operated primer bulb till stiff.------Remove drain screws on carburetor bowls.-----Is there fuel in both carburetors ?

 

[racerone]

New VRO pump from factory or something else from CHINA ?

 

[sean408]

i will check it tommarrow and update. but i do not have a vro anymore converted to a regular fuel pump and premix this problem happened after i rebuilt the carbs and i rebuilt them 2 times with 2 seperate rebuild kits different brands. im also going to check the fuel lines for debri although with a filter there shouldnt be anything clogging it. i did notice cylinder 1 plug was wet and cylinder 2 was dry found out that the new ignition coil was bad put an oem one on. since the aftermarket one was junk but i fixed all the before i took it out on sunday