92 Johnson 40 Hp idle

[sankstone]

I purchased a 92 Johnson 40 VRO. Disconnected the VRO and run 50:1 via local dealer. This motor won't start. It wants to but it won't idle. If I push the plunger and keep it revved I can get it going. It runs great at slow and faster speeds. It just wont start and idle. I suspect carbs. Looking for any suggestions. If there was a tank problem, I would assume it would be there at all speeds. Maybe I'm incorrect. It pumps up fine. I have a plastic tank and keep the cap on tight. Is there a low speed idle that could be causing this? I have not taken the carbs apart.
Tom

 

[Daviet]

Re: 92 Johnson 40 Hp idle

Item #23 is the low speed adjustment screw, start at 1 1/2 turns out.http://www.ishopmarine.com/ishop/jsp/AsplIsmCcatViewBase.jsp?&lvlCode=5&pCode=C0045154&path=BRP~A0000003~M0002683~M0002805~M0002806~C0045154&isFromCMS=false&hideAdd2CartButton=&isStandAlone=&is4CmsShop=&reqln=Unknown&reqem=Unknown&reqph=Unknown&reqFor=29&req4Browse=1&docId=&docName=&isForSupStore=false&cCatFilter=&eCatSupFldr=

 

[sankstone]

Re: 92 Johnson 40 Hp idle

Wow, thanks for the link. I looked all over for something like that.

 

[tashasdaddy]

Re: 92 Johnson 40 Hp idle

wait on adjusting # 23. idle the idle stop screw was set with the engine on muffs, it will not start, when the leg is in the water. setting idle stop screw on muffs the Rpms, need to be set at 1,000 rpms, then final adjustments in the water and in gear. the reason, of muffs, there is not any BACKPRESSURE on the exhaust. # 23 could be set fine.

when setting # 23 you turn 1/8 of a turn, and wait 15 seconds for the motor to respond. you only adjust ONE carb at a time, no going back and forth.

 

[sankstone]

Re: 92 Johnson 40 Hp idle

Ok, sorry, I don't have a manual. I know it's a good idea. I will look into that soon. For the record, what is #23 ? I assume it's a idle screw or something?
There is a slow speed idle on the left side as facing the carb and another one top center of the throat of carb? I did look at a schematic of the carb and there
are numbers for the front idle. It says 15" and 20" upper and lower. What is the
15 " and 20" ? Obviously I've never done this before. I can't afford to take it to
a mechanic. I have already sunk too much money into the lower unit. Trying to
solve as much as I can. Thanks

 

[sankstone]

Re: 92 Johnson 40 Hp idle

OK, I see what you are saying. #23 refers to the schematic slow speed idle. So what is the idle on the front throat?