First time in the water = fail!

[gus-gus]

Re: First time in the water = fail!

Don't confuse the gasil ratio "lean" with the fuel:air ratio "lean". A lean fuel:air ratio will certainly cause a backfire on that twin. Also, the advice for "50:1 for all 2 strokes" is BS. If your idea of an old engine is 1983, then you would be correct, but the early/pre-1960's twins may not have a complete set of roller bearings and will suffer greatly at 50:1. Try running a 1960 3 hp on 50:1 and see how long it lasts.....

I am not confused, I ran 1950's engines for years on 50/1 mixture. Not one issue.
This is the exact same year and even the same color motor I owned for 18 years, running 50/1 in for 10 of those 18 years. I ran it exclusively on my lake from my dock and both my children operated the same motor day after day on 50/1. I sold it in 2008 and the guy is my friend and says it still runs perfectly.
http://www.ebay.com/itm/Vintage-Elg...ear&vxp=mtr&hash=item2c60d30bcd#ht_500wt_1344http://www.ebay.com/itm/Vintage-Elg...ear&vxp=mtr&hash=item2c60d30bcd#ht_500wt_1344
I have ran 2 smokers for 50 years. I have rebuilt many as well. Bushing and roller. 50/1 oil is better today than the oils were when 16/1 was prescribed

 

[HighTrim]

Re: First time in the water = fail!

The oil is better today, no argument there, that is why it does not smoke as much nor foul the plugs as often, if ever, mixed at 24-1 or more.

50-1 mix on the pre 64 motors, as well as the smaller hp motors tires them out incredibly, if not destroys them. You have been lucky so far. Im sure the powerhead is in nowhere near as good a shape as a similar motor run with proper lubrication.

To each their own, they are your motors. Just stating what is reccomended for maximum lifespan.

 

[CPTom21]

Re: First time in the water = fail!

I had a similar issue with my 40hp 1964 Big Twin. All I had to do was spend about 2 hours playing with the lean/rich nob with the engine running(I did this in the driveway not the water obviously). I was advised to use a 50:1 ratio when I bought it, and since I got that tiny issue with it turning off when it was under 25% power it's been sounding amazing. IDk if this helps, but it may be something as simple as a turn of the nob.

 

[1946Zephyr]

Re: First time in the water = fail!

By 1961, the only motors that didn't have needle bearings were the old Lightwins. They were 100% friction based motors. These I generally would recemend 16:1 The later designed 4hp, was slightly improved with the needle bearings on the top crank journal. These I would recemend 24:1 As a rule, any motor that has no needle bearings should be run on 16:1 and no leaner than 24:1 after all, they're basically the same construct as the old TD/TN johnsons. The motors with 100% needle bearing set ups, are okay to run on 50:1 on the earlier model, but don't ever get it hot. You'll score the pistons out way quicker, than the 24:1 motor will. Richer oil mixes are mostly for the sake of the connecting rods and crank, than the pistons, eventhough I was told that the earlier motors did have a softer alloy piston and 24:1 was a better mix to run. If you look at the part numbers on the pistons for a 1965 18 or 40 and they are the same as the part number for the 1960 models, then I guess it's hard to understand why a lighter oil mix is justified, other than political reasons. The tree hugging liberals hate us running our smokey old antiques in the waterways, so they have lobbied against these manufacturers to build motors to run on less oil. By the early 80's, pressure got worse and OMC (and maybe others) decided that 100:1 was suitable.....well, not really. OMC recalled bunches of these 100:1 motors and rebuilt bunches of powerheads for the customers. Oil is the cheapest thing you'll ever put in your motor, so we know it's not to save us money. To further prove my point, they want Ford to build an F-350 that gets 30 miles to the gallon. It's all about politics and the environmentalists.

 

[Gas Giant]

Re: First time in the water = fail!

Wow this thread really took an unexpected direction.

Anyway, back on track, the slow speed needle had vibrated loose and wasn't where I had set it originally. I tightened down the packing nut a bit tighter and reset it 1 1/2 turns out, but it didn't appear to have an effect on the backfire/sneezing issue. When I set the needle the first time, it didn't backfire/sneeze at all when the needle was 1 1/2 turns out. The engine's backfiring/sneezing actually shut the engine off before I could make any adjustments, so I decided to stop for now.

So tomorrow, I am going to pull the flywheel just to see if there are any ignition issues. (Sheared flywheel key, or anything amiss on the armature plate) I may pull the carb also and see if it somehow got crud in it.

And, as stated, I still have 100psi dead even on both cylinders, so hopefully nothing is wrong internally.

I'll report what I find.

 

[1946Zephyr]

Re: First time in the water = fail!

Too bad they did away with that inspection window on the '62 and later motors. That would make things a lot easier, as far as checking your points. I wouldn't worry about the carb. All you need to do, is remove the plug and drain it and you'll see if there's any debris in there. The filter in the fuel pump, should stop anything large enough to foul the carb. I'm thinking a set of points is probably out of adjustment.

 

[Gas Giant]

Re: First time in the water = fail!

Ok, got it going again. But it wasn't easy. I'll post what I found and what I did for future searches.

First thing I did was pull the flywheel. The flywheel key was intact. However, I quickly noticed that one of the coils had a pinched ground wire and exposed copper. I swapped the coil out with one from my other engine, re-checked the point gap on both points, and carefully made sure all the other wires were dressed in a way that they would not get pinched.

Reinstalled the flywheel, and to my disappointment, fixing the pinched wire had no effect on my problem. It was still snorting like mad when it ran. I re-checked every fuel line, every fitting, every hose clamp, to make sure everything was tight and secure. It was. No amount of adjusting the slow speed needle had any effect on the backfire/sneeze/snort/whatever you want to call it.

I checked for spark, and I had a nice blue snap that jumped a 7/16 gap on both cylinders. So I concluded that the ignition was functioning properly at this point.

I then went to remove the carburetor (which requires removing the electric starter, and removing that requires removing the pull starter), and noticed that the choke housing was very loose. So I took it apart, tightened it back down, and put everything back together. I wanted to make sure I was taking a scientific approach, so I would only correct one problem at a time. As expected, however, this had no effect on my problem.

Running out of ideas, I decided to simply swap the entire carburetor. I had initially put the freshly rebuilt carb from my '61 on this motor, but I put the original '63 carb back on it. I reset the slow speed needle to 1 1/2 turns out after installing the carb, and viola, the problem was gone. The problem was in the '61 carburetor. (I readjusted the SS needle per Joe Reeves's directions afterwards)

However, as an apology to all of you, I did inadverently leave out a key piece of information. Earlier this week, or perhaps last week, I posted a thread on having trouble adjusting the SS needle, where I said that I had turned my packing washers into "shredded wheat". I thought I had done a good job cleaning the bits out, but evidently I hadn't. And since I never told any of you that, you didn't know to tell me that was a problem. (I should have known, but I'm still learning the hard way here :redface

So, this whole thing was caused by the remnants of the packing washers left in the SS needle cavity of the '61 carb. Although undoubtedly, the pinched coil wire would have become a problem very quickly.

Thus, thanks to all of you who replied.