115 carb on 140 engine

[jayhunt3]

I bought an '83 140 Johnson rebuild that has a 115 carb. I know the hp will be limited to 115 but are there any other issues that I need to watch for using the smaller carb? Thanks

 

[Dhadley]

Re: 115 carb on 140 engine

It will not necessarily limit the horsepower. It will run just fine. You will have a very responsive and economical 140 crossflow.<br /><br />I have to ask -- you said "A 115 carb", are they both the same and how do you know they are off of a 115?<br /><br />Just curious......

 

[R.Johnson]

Re: 115 carb on 140 engine

As I recall on the 140, they had a 1 3/8 venturi as apposed to a 1 5/16 on the smaller engines. Did they change the intake manifold when they changed carbs? The 140 also had rubber stuffer blocks in the manifold, I'm not sure if the smaller engines did. The 140 also had a different exhaust tuner. My main concern would be a lean mixture. Why did they go to the 115 carbs? I would like to see Joe Reeves, or Rodbolts thoughts on this. They may have a better answer on this, as I'm not sure.

 

[jayhunt3]

Re: 115 carb on 140 engine

I was told that the original carb on the 140 was shot and the had a spare 115 carb. I am not sure if they changed the intake. Please let me know any questions that I should ask while the engine is still under the warranty period and they have a reason to respond. I believe the cylinders have been bored slightly larger as well as part of the rebuild. Thanks.

 

[R.Johnson]

Re: 115 carb on 140 engine

Ask if they changed both carbs, or do any rejetting. The size of the venturi would be on the face of the carb, this number is cast in place.

 

[Dhadley]

Re: 115 carb on 140 engine

The intakes, adapter plates and the tuners were the same for the motors you are working with. We have done this many times and the motor should run fine. There were some rubber stuffers in the intake on the 140's and some showed up in some years for the 115. They were discontinued in later years. We never saw much difference with or without them under 6500 rpm. <br /><br />The smaller venturi will give you slightly better throttle response and be slightly better on fuel. As long as the motor is running OK and is capeable of your target rpm, you should be good to go.<br /><br />Is the motor running OK now?

 

[jayhunt3]

Re: 115 carb on 140 engine

Thanks for the reply. The motor is just 15 hours past rebuild. The enngine runs great from 1200 to WOT but will stall occasionally at idle. Sometimes in nuetral the rpm will drop to 400 to 600 and then stall out. Any suggestions? Thanks

 

[AUGIDAWG]

Re: 115 carb on 140 engine

Check the idle throttle stop and cable tightness.<br />When you slowly move the throttle lever from "in-gear" to neutral, the throttle stop should be touching the block. If it doesn't, but does when you move it back rapidly, the cable is loose, and the idle stop screw needs to be turned clockwise, just so the slow and fast movements results with the stop touching the block.<br />This is part of the "Link-and-sync", but you don't need to spend $300 to make a 5 minute adjustment.