1972 25hp Johnson

[EARLS BOAT]

Re: 1972 25hp Johnson

It Is In Arkansas

 

[woodducker]

Re: 1972 25hp Johnson

sounds like that is a coil problem on the 69 model.

 

[jspringator]

Re: 1972 25hp Johnson

I Have A 69 20hp Johnrude That Idels Really Well But If I Idel For A Long Period Of Time And Then Try To Run Wot It Will Stall And Run Slow But Will Sometime Suddenly Come Alive And Hauls Tail. Almost Threw Me Out The Boat The First Time It Did It! Is This Possibly The Same Retrofit THAT CAUSES THIS?

The 69 already has the perfect set up.

 

[samo_ott]

Re: 1972 25hp Johnson

Well, I'll tell you this much: The 1970 still dumped the crankcase drains into the exhaust, a system that had been in use for years. Starting with the '71's they routed the crankcase drains into the upper cylinder via the bypass port. The idea of course is to burn the excess fuel instead of dumping it. But the reality of it is that that just makes the upper cylinder run rich compared to the lower cylinder. Reality also says that the extra rich fuel in the top cylinder doesn't completely burn anyway, and it still winds up going out with the exhaust.

It is simple to retrofit it back to the 1970 system. But not so simple as just installing the hose fitting. Drilling is required. And the drilling is also simple if you know where/how. The result is exactly like the 1970 motors. Powerhead removal is not required.

Now, the question is---do I give instructions for a process that might violate EPA mandates or not? I don't want anybody to get in trouble, especially me.

Why wouldn't they come up with a system where they ported it back to the carb and thus got evenly distributed between the 2 cylinders? Would have made more sense. How long did this system last and what superceded it? Something even 'better' I assume?

 

[jspringator]

Re: 1972 25hp Johnson

1976 was the last year for the 22 CID 25hp. The 77s were more powerful,.... and were heaver. Designed in emission control always works better than an ad on. This block was used for the first time in the late 50s.

 

[EARLS BOAT]

Re: 1972 25hp Johnson

I Was Thinking The Same Thing About Dumping Back Into The Carb. IT MAKES SENSE TO ME.