Old 2 stroke vs new outboards (2&4) stroke

[reivertom]

I love old OMCs and most any other old timer, but I can’t take anything away from my mid 90s Honda 50hp. I didn’t run it for over 10 years and it sat in the yard covered up. I have this problem selling things I might want to use some day, so there it sat on a boat. Last summer, I fogged the cylinders, pumped up the gas line and it started like I had just shut it down. I don’t know if this is normal, but mine has been a great motor. I just miss the 2 stroke smell though.. :^)

[Pete]

My race 2 stroke simple ‘SSBB’ engines were shut down in late 1979 after leaving APBA racing, they sat in the garages of 5 houses I moved from and in 2008 started them up with no real issues. I did rotate them over every 8 or so years and changed the gear lube on occasion. They are a 1973 Merc 25ss CD ignition and a 1976 Yamato Y80 points ignition both 2 cylinder jobs. When I shut them down drained all fuel and flooded with OB oil. Presently use them regular at AOMCI meets.

[jerry-ahrens]

The big disadvantage of the 4 stroke fishing motors (IMO) is the weight. the carbureted models don’t do well setting around with old gas in them…. ethanol is a death sentence to the fuel system. To be fair though, many of these engines that fail to start or are hard to start, is due to lack of proper care and maintenance. Like I always say, fill it up with ethanol, go fishing, push the stop button and put it in storage… The tiny passages in the Japanese carburetors are easily plugged. On the other hand, if cared for properly, they are nice running engines. I have a 2003 115 Merc (fuel injected) in the shop right now, that has set for 2 years with old gas in it. I’m not sure if it had ethanol in it or not. It was running on 3 out 4 cylinders, once we were even able to get it to start. But again, it was just turned off and left setting, so it’s hard to blame the engine.

[reivertom]

quote Jerry Ahrens:

The big disadvantage of the 4 stroke fishing motors (IMO) is the weight. the carbureted models don’t do well setting around with old gas in them…. ethanol is a death sentence to the fuel system. To be fair though, many of these engines that fail to start or are hard to start, is due to lack of proper care and maintenance. Like I always say, fill it up with ethanol, go fishing, push the stop button and put it in storage… The tiny passages in the Japanese carburetors are easily plugged. On the other hand, if cared for properly, they are nice running engines. I have a 2003 115 Merc (fuel injected) in the shop right now, that has set for 2 years with old gas in it. I’m not sure if it had ethanol in it or not. It was running on 3 out 4 cylinders, once we were even able to get it to start. But again, it was just turned off and left setting, so it’s hard to blame the engine.

I always unplug the fuel lines and run the gas out of my motors on the way to the dock. I then pull the choke and milk all the gas I can out of it as I turn it over a few times.. If they are going to sit a long time, I drain the carbs on any motor, 4 or 2 stroke.

[outbdnut2]

I also run the gas out of motors I don’t plan on using for awhile. A friend of mine has 4-stroke 25 HP Suzuki and he no longer runs the gas out except at end of season because it uses so little gas at idle, he says it takes almost 20 minutes to run it out, and that’s too long to wait at the landings he uses. My 2004 25 Yamaha 4-stroke pontoon motor runs out in just a few minutes if I step the idle up a bit.
Dave

[outbdnut2]

quote twostroke:

My poor old pontoon boat that my wife and I use on almost a daily basis when the water isn’t ‘hard’ has a 30 yr old OMC twin that just plain runs.
Jim

My Dad bought 1987 30 Evinrude new back then when he bought his pontoon which I now have. Like your similar or same motor – yes – it always ran….but….like a lot of those era OMCs in that HP range, it had a fairly wide throttle range where it did not run smooth as it was in transition from the low to hi speed carb jets. The speed we want to idle around the lake is in the middle of that rough running range. I could only alter that slightly by adjusting the low speed carb needle, and then it didn’t idle well at slower speeds. This rough running and "4-cycling" of the 2-stroke engine made it noisier and it was marginally Ok until my wife took a ride on a neighbor’s pontoon with a 4-stroke. I didn’t hear the end of it until 2004 when I bought a new 25 Yamaha 4-stroke for it. I’ve noticed on several similar motors, this rough-running throttle range is (in my opinion) unacceptably wide.
Dave

[fleetwin]

quote outbdnut2:

quote twostroke:

My poor old pontoon boat that my wife and I use on almost a daily basis when the water isn’t ‘hard’ has a 30 yr old OMC twin that just plain runs.
Jim

My Dad bought 1987 30 Evinrude new back then when he bought his pontoon which I now have. Like your similar or same motor – yes – it always ran….but….like a lot of those era OMCs in that HP range, it had a fairly wide throttle range where it did not run smooth as it was in transition from the low to hi speed carb jets. The speed we want to idle around the lake is in the middle of that rough running range. I could only alter that slightly by adjusting the low speed carb needle, and then it didn’t idle well at slower speeds. This rough running and “4-cycling” of the 2-stroke engine made it noisier and it was marginally Ok until my wife took a ride on a neighbor’s pontoon with a 4-stroke. I didn’t hear the end of it until 2004 when I bought a new 25 Yamaha 4-stroke for it. I’ve noticed on several similar motors, this rough-running throttle range is (in my opinion) unacceptably wide.
Dave

A legitimate complaint indeed about the OMC 32CI models of this vintage…
Don’t be afraid to deviate from the cam pick up adjustment slightly to alleviate some of this. This all started in the early 70s when the overboard drains were eliminated. IMHO, the recirculation system feeds the two cylinder unevenly making it impossible to get a real smooth idle/off idle adjustment. I would have thought engineering would have improved the recirculation system when the 32CI engines were developed, but the same poor design carried over from the 22CI engines. I can understand how this would be a major complaint on a pontoon boat.

[twostroke]

Yeah. I tampered with mine when I bought it to get it to run smooth (for what it is) just off idle…..that’s where we run at virtually all time. I don’t remember exactly what I did….but I know it involved stealing some parts out of an older carb I had laying around. My boat gets run WFO twice a year. Across the lake when I put it in….and across the lake when I’m taking it out. Other than that….it’s slow ride just offa’ idle. I tuned out the stupid behavior you’re describing at the expense of midrange. Halfway into the high-speed jet this thing kinda’ "lays down", then runs good at full tilt. It is what it is. Cheap, indestructible, sorta’ crude, but ALWAYS runs. If I want high tech, I can go on my buddy’s tri-toon with two (yes, two…) 300HP E-tech monsters(65 mph. Who want’s a pontoon that goes that fast? I’d rather have my old B hydro…) that cost nearly what my house, shop, and lakefront is worth. To each his own….

Jim

I say "pardon me" a lot. I had a 20H, then raced open mod sleds.

[jeff-register]

My last 4 stroke was a briggs / stratton & all my stuff is leaded gas vintage…so I use Av gas & factory brand pre-mix. Yes, all the maint above
I always had no start problems with Merc or OMC if tuned & not a leaker. Fact check before going out,

[outbdnut2]

quote twostroke:

Yeah. My boat gets run WFO twice a year. Across the lake when I put it in….and across the lake when I’m taking it out.

Jim

That’s when mine gets opened up too!….and occasionally if a storm comes up quick, and …oh yeah… it runs full tilt back to the dock if someone has to go to the bathroom and doesn’t have a swimsuit on! (I added a small ladder to climb back out of the lake).
Dave

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