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Carb question

I am not sure how a motor like that can get down to 15 PSI compression.----There should be obvious damage at 15 PSI-----I would say your gauge is suspect !!!
 
Have you any history of the motor or did you just get it? You rebuilt the carb to start with but did it run before that and what were the symptoms? Is the paint discolored on the cylinder head? How did the cylinders look, were they scratched or nice and smooth and shiny? Have you got some pictures of the motor, where do you live?
 
Sometimes i have just cover the spark-plug hole with my finger, and then pull the rope couple times. I can feel clearly the pressure in my finger. This feeling tells me something, but of course it is not same as the gauge would tell. As a general rule; when putting spark-plugs back, it should done with great care, make sure that it sits good in thread, and use right torque. Make sure you have the metal gasket there. I have no any torque-wrench for spark-plugs, but i always first tight the plugs with fingers as much as possible, then with traditional spark-plug tool almost (not full) 1/4 turn more.
 
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I bought it from a guy who was just getting able to sell his late fathers collection. He collected and worked on them as a hobby.
The guy used gas filled spray bottle and sprayed into the silencer to start it up in a tank and it ran as long as he kept spraying fuel.
He did this because when he had unscrewed the tank cap it was difficult due to lacquer and corrosion build-up. His Dad had stored it
dry with the petcock closed and no gas in carb but seeing this he assumed the tank should be cleaned before introducing gas to it and the carb.
I started to go through from top to bottom with the help of this forum and another. I found that he must have gone through and replaced
all the ignition parts as well as installed a carb kit. I had already bought a new carb kit not knowing he had already installed one.
I took the carb apart and cleaned it up and reinstalled the kit. That's the history of it, he did mention none of his Dad's motors ever saw salt water.
The compression checker I just got is a harbor freight cheapy. I have a very good running merc 2.5 that I'm gonna use this gauge to see
what it shows for compression, I think that will tell me if the gauge is suspect.
 
By the way, when I do put my fingers over the spark plug holes there is pressure. I
had one local guy tell me that my rings could be cracked from engine running with incorrect
fuel/oil mixture. First I heard of that possibility.
 
Makes me feel really sad, to know that your motor has been running with start-spray only. Perhaps engine has been running without any oil and that is not good. Rings could be cracked, cylinders wall could be scored too. Yes i think it would be best now to get right compression reading. If real readings are too low, you might need to re-finished (honed) your cylinders. Also new (good used) rings too, hopefully pistons are ok. But lets get right readings and see what happen. These are just so nice engines.
Check out my 3hp project from here:
http://www.marineengine.com/boat-forum/showthread.php?451657-Evinrude-3hp-1966-rebuild
 
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Cylinder head was off.----Rings were said to be " springy "----At 15 PSI there would have been obvious damage to rings and cylinder walls.-----None was reported !!----Test with another gauge.
 
Does it have discolored paint on the head? Overheated then. I buy these all the time at sales, repair them, then sell. If I see discolored paint, I am not hopeful of a "sweet ride".
 
My Lightwin had some discolored paint at the moment i started my project. I think that those are possible to return service, but it need a lot of work of course. I really love these small engines and i think that practically all of these, deserve new life, just like my Lightwin. After hard work, it is very nice to enjoy classic motor.
 
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Yes, to effectively engineer a twin cylinder outboard so small and light, and to last for 70 years, is nothing short of "brilliance". Engineers today may have that intelligence, but it is directed at making money by creating products either to fail, or become obsolete. Does anyone out there really think that a 2019 Yamaha will still be around in 2089, will you be able to get parts for it? Among my fellow senior techs, along with fine mechanics like Evin, I'm probably "preaching to the choir".
 
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That is right, and i think that keys to long-life are simple construction, good materials and of course right use with regular service. With right use, i mean that no full throttle just after start, and never constant full throttle operation.
 
Good call racerone, I tested my good running 2.5 with same gauge and barely got 30psi.
I went out and bought a different gauge and presto my 2.5 was just over 100 psi.
Used the different gauge on my jw-16 and it has 70 psi on top and botton cylinder.
Should it run with 70psi.
 
That's like brand new, brother. Racer didn't just "fall off the turnip wagon". We ALL learn from that dude.
 
I'm learning from all you folks, so glad I stumbled onto this forum .I am also on another forum that has been very helpful as well.
I'm getting a good 5/16 spark jump on #1 but sporadic on #2 and only jumps 3/16 at best. Only sparks about every other rope pull.
Getting ready to check coil for loose wires and spark plug wire for damage.
 
Probably dirty or poorly adjusted points. You said new coils too, right? Make sure the plug wire is pushed all the way into the coils and the needle protruding from the coil is centered into the plug wire. Check boot at plug end for proper conduction.
 
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Make sure that all connections are clean and tight. When putting coils back, make double-check that they really sits in right way, so that inside of the flywheel will not touch the coils heel.
 
In the photo you can see what was the cause to my weak ignition. The ground-wire was very bad, even everything looks very nice. Photo is taken just in the begin of my whole engine rebuild project, now i have good spark after putting new coil there. Watch the red arrow.

Ignitionbefore.jpg
 
The points and coils just looked new too me. I cleaned and reset points and still have weak and intermittent spark on lower cylinder.
Not sure what I'm doing for sure but removed the coil and checked with my meter by watching a how to check coil video. I know, I have been
steered wrong before watching youtube. Anyway pretty straight forward video. The primary winding reading was 1.2 and secondary
was 4.572 give or take. I then removed the coil that has good spark and the primary reads 0.9 and secondary pretty much around
what the other read. The video had two coils and both had primaries in the 0.7 and 0.8 range with secondaries 3.750 give or take.
Guy just said the were good. Left out what range you want to see to determine what would be bad.
Also my coils have this green laminate that covers the metal, it's kinda flaking off in spots. Should this been cleaned off?
 
sorry racerone our post timing was the same.
What about the readings I get. I think I read in a post any primary reading above 0.9 is bad?
 
Try setting a proper air gap on the coil.----And try setting the points with a meter and timing marks, instead of feeler gauges.----That should get you proper spark.----These magnetos are wonderfully simple if you understand how they work !!
 
Thanks racerone,
I do have good spark at each plug now.
I timed it with my meter and all went well but wasn't sure what throttle position
I should be in, I did it in the start position. Set the air gap on the coil.
I have to tell you guys though I heard it run for the first time since I've had it just 10 minutes ago.
Runs like crap but it does stay running. Problem is when I advance the throttle not much happens RPM wise.
I definitely think I need to learn the low and high needles. I can get the RPMS up and down playing with the needles
which obviously I should be able to but clearly my inexperience is shining through here.
I was able to get the timing marks dead on so I think it's a carb issue now. Any thoughts
 
Hopefully not air-leak between carburettor and intake manifold. Generally i think that Infra-red temperature gauge is good tool when servicing outboard motors. With that gauge, you could example see if motor is running too lean, then operating temperature is too high and that is dangerous to the engine. And the air leak will lead to the too hot engine.
 
Question about the low and high speed needle valve adj handle locations at initial settings.
So I preset my low speed 1 1/2 turns out from seat and high speed 1 turn out from seat.
At these settings should I be installing the handles pointing at #1 on their respective lean/rich scales?
 
The initial settings are so that motor will start and keep running.-----It is up to you to adjust these on the boat for best performance !!------Adjust high speed ( lower ) first at full throttle.-----Then adjust the idle mixture with motor at low throttle setting.------Then you can put the knob wherever you like.-----Perhaps in the middle of the rotation.
 
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