2001 Johnson 90 won't idle.

[Cashpoboy]

I recently rebuilt my Johnson 90 '01 model J90PLSIF.<br />Will idle for short period and then die. At the lake it dies immediately when put in gear. Runs perfect at higher speeds. Will run on idle temporarily when start key is pushed to prime. It acts like it is just not getting fuel but I cannot seem to get it to draw fuel. Could this be something to do with the VRO? <br />Low speed mixture screws are opened 5 3/4 turns as per OMC manual. All jets are clear (checked so many times I can't count). #1 piston had hole in top so bored over 20 thousandths and put back together following OMC manual. Compression 120 give or take a pound or two in each cylinder. All four carbs rebuilt and thoroughly cleaned. <br />There appears to be two fuel pumps, one at the VRO and the other at the top of the vapor seperator. Could one of these be the problem? Has anybody out there had one of these do this? Want to go fishing not tinker with this. Thanks for any help.

 

[rickdb1boat]

Re: 2001 Johnson 90 won't idle.

I hope that open "5 3/4" turns open is a misprint. 2 3/4 sounds more like it...

 

[Solittle]

Re: 2001 Johnson 90 won't idle.

"Will run on idle temporarily when start key is pushed to prime" tells you you got a fuel problem as you suspect. The fact that it runs well at higher speeds (What rpms? - WOT??) indicates you have carb problems.<br /><br />When you rebuit the carbs did you disassemble, soak, blow out with compressed air and put in new kits? A lot of guys post that thie carbs have been thoroughly cleaned and they have been - - on the outside. The crud that gets you is usually on the inside in places you can't easily see.

 

[Cashpoboy]

Re: 2001 Johnson 90 won't idle.

Carbs are most definitely clean. Every jet,orifice, channel, the whole shabang cleaned multiple times. They are spotless. Could this be a crankcase leak of some sort, maybe the rings that divide the crankshaft and seal the individual chambers in the case from each other? How can you tell if these are worn? Also how do you check for crankcase leaks? I have worked on engines for years and this is a stumper. Thanks

 

[Cashpoboy]

Re: 2001 Johnson 90 won't idle.

It turns out that the low speed mixture screws were not out far enough. The OMC manual says 5 3/4 turns from seat but it was more like 8 or 9 turns out. Thanks for your help. <br />Next problem, how do you balance the carbs so the mixtures at idle are correct for each carb?