Johnson 140 V4 Commercial Engines?

[DUKE1]

How can you tell if you have a "commercial" engine? I saw a post talking about some V4's with V6 gearcases. I also noticed that some V4's have 13 spline shafts and mine has 15 splines. My 140 looper is 1986. If it is a commercial engine whats the difference? Do they have a different WOT than a recreational engine? Are their any pro's or con's to a commercial engine?

Thanks.

 

[ezeke]

Re: Johnson 140 V4 Commercial Engines?

Edit

 

[ezeke]

Re: Johnson 140 V4 Commercial Engines?

The 25" gearcase is a V6 gearcase with the larger prop shaft.

 

[Dhadley]

Re: Johnson 140 V4 Commercial Engines?

In the V4 looper line the commercial motors, like some 20 & 25" recreational models, had a V6 style gearcase. Yes, it has a V6 propshaft but it has a gear ratio slightly different than the V4 or the recreational V6. And it has a rather small driveshaft end and pinion nut. Don't ask - I have no idea why they'd make the most critical part in the gearcase that small.

The commercial V4 looper had the old style fuel pump, in fact it had two of them. Obviously there were some styling differences too. Some V4 looper commercial motors had some very large chamber heads. Some "overseas" commercial models could run on some remarkably low octane (thats what they have). Some had a rev limiter well below what the recreational motors have.