NO START AFTER LOWER UNIT REPLACEMENT

[syork6197]

SO I BLEW OUT MY LOWER UNIT LABOR DAY LAST YEAR, LONG STORY SHORT AFTER COMPLETELY REDOING MY PONTOON AND REPLACING LOWER UNIT I HAVE A NO START ISSUE. MOTOR WOULD START AND RUN JUST FINE BEFORE PUTTING ON THIS LOWER UNIT. MY MOTOR IS A J90MLCDC 86 MODEL 90HP, LOWER UNIT CAME OFF OF A BLOWN J115TLERC 94 MODEL 115HP. EVERYTHING I CAN FIND SAYS THE TWO UNITS ARE INTERCHANGABLE, BUT NOW MY MOTOR WILL NOT TURN OVER TO RUN. WITHOUT THE LOWER UNIT ON, MOTOR WILL BUST OFF AND RUN AFTER ONE SPIN. IM SO CONFUSED AND JUST ABOUT TO PUT THIS THING IN WATER WITH A BUNCH OF HOLES IN IT. PLEASE HELP

 

[racerone]

There were changes made in the area of the splines on the crankshaft.----And yes when you install the lower unit of a newer motor there will be a problem.----So if you back off the lower unit bolts 2 turns the motor turns easily by hand ( sparkplugs out ) and it jams when you tighten the screws ?

 

[syork6197]

I HAVE NOT TRIED TO BACK THE SCREWS OUT AND TURN IT. ARE THE SPLINES DIFFERENT, FROM ALL THE RESEARCH I DID BEFORE HAND IT SHOWED THEY WERE INTERCHANGABLE. SO CONFUSED AS TO WHAT NEEDS TO BE DONE HERE. I JUST WANT TO GO TO THE LAKE. LOL

 

[racerone]

No the splines and count are not different !!----The issue is changes made in length of splines and depth of the hole in the crankshaft !----Back all the bolts out 2 turns and tell me what happened.-----Sorry , I am not there to help you and point all this out.----I discovered this issue years ago !

 

[syork6197]

I WILL TRY THAT TONIGHT, IF IT WORKS CAN IT BE RUN THAT WAY?

 

[racerone]

No you can not run it that way.----This is suggested simply to assist you in trouble shooting.

 

[syork6197]

I HAVE A FRIEND WITH A MACHINE SHOP, COULD THE SHAFT BE SHORTENED AT A MACHINE SHOP TO CORRECT THE ISSUE.

 

[racerone]

I believe your machinist friend can assist with where the interference is happening.---You could use a mini grinder and take 1/8" off the drive shaft.----See if that solves it.

 

[syork6197]

Thank you

 

[syork6197]

Took an 1/8 off an inch off and it turns better but won’t start. Should I take a little more off?