1975 Evinrude 9.9 no start

[kalebg]

Cools not lubricates. Of course it has lubrication.

 

[kalebg]

[No message]

 

[flyingscott]

Cools not lubricates. Of course it has lubrication.

How does it not Cool? You may want to get with somebody who has some kind of 2 strk knowledge. Somebody who can tell you how things work in person.

 

[kalebg]

It does cool, but because of it limited volume its primary job is lubrication. Because there is 50x more fuel in the cylinder than oil? Because if you burn a gallon of fuel in say an hour you have 2.5 oz of oil vs 125 oz of fuel? And cooling capacity is largely affected by volume and specific heat capacity of the "coolant". And the combusion causes the oil to burn away? Hence two stroke smoke? Or I mean the 100 years of internal combustion engine experience literally cataloging the dangers of running lean. I mean that image is literally a mechanics page on diagnosing pistons damage in 2 strokes just for some validation. I mean 3x he says lean kills pistons. Clogged fuel filter? Fuel starved-runs lean. Air leak behind the carb? Extra air same fuel-runs lean, and then blatantly carb adjusted lean.

Lean burn causes excess heat. This excess heat in directed at the piston. The piston having little contact with cooled walls of the cylinder via the rings is not cooled directly and get hotter unless cooled by the incoming proper charge of air, fuel, and oil. The combustion leaves a film of the unburned oil deposited on the combustion chamber and some oil is burned in the process. Small defects and even small pieces of carbon in the head and piston in the combustion chamber when ruunning lean can conduct this excessive heat creating a "hot spot" in the cylinder. This hot spot preignites the mixture on the combustion stroke. This combustion is rapid and violent and both creates more excess heat and applies force on the connecting rods at an angle prior to TDC. This is what is known at spark knock pinging and detonation. This can also cause pinpoint heat to surfaces splattering particles of molten aluminum inside the combustion chamber.

 

[racerone]

When running , the piston in a 2 stroke is coated with oil just like a 4 stroke engine.

 

[tomhath]

Or I mean the 100 years of internal combustion engine experience literally cataloging the dangers of running lean.

Use good quality gas with the proper amount of oil and adjust it so it runs smooth, you won't damage it.

 

[Tim Frank]

^^^
what he said.
You are over thinking this....and underthinking most of the other advice
offered. Perhaps "not reading it all"?
Check post23...you have a 15 hp frankencarb on a 9.9 hp. Motor,...in an unknown configuration. ...and it is not running smoothly?
Hard to believe.....said no one.

Check the jetting.....who knows what "design improvements" the last owner made.

 

[Tim Frank]

It does cool, but because of it limited volume its primary job is lubrication. Because there is 50x more fuel in the cylinder than oil? Because if you burn a gallon of fuel in say an hour you have 2.5 oz of oil vs 125 oz of fuel? And cooling capacity is largely affected by volume and specific heat capacity of the "coolant". And the combusion causes the oil to burn away? Hence two stroke smoke? Or I mean the 100 years of internal combustion engine experience literally cataloging the dangers of running lean. I mean that image is literally a mechanics page on diagnosing pistons damage in 2 strokes just for some validation. I mean 3x he says lean kills pistons. Clogged fuel filter? Fuel starved-runs lean. Air leak behind the carb? Extra air same fuel-runs lean, and then blatantly carb adjusted lean.

If you adjust the slow speed setting too lean, as already stated, itwill just stall..... no damage.

If you are adjusting the high speed setting, you have a dinosaur carb. It should have a fixed jet.....no adjustment possible except by chaging jet size.

That may have been done by a previous owner.

 

[kalebg]

Except in a 4 stroke there shouldn't be oil in the combustion chamber. Also it needs an oil control ring to prevent excessive oil on the cylinder walls. Plus it inherently has more oil being directed at the big end bearing wrist pin bearing and thus the underside of the piston becasue engine bearings require substantially more lubrication to float the 2 surfaces apart than 2 stroke needle bearings that can actually run with a marginal amount of lubrication.

 

[kalebg]

Its not a franken carb. Its literally a 15hp carb of a 15hp evinrude . So untouched it still had the original cork float and rebuilt with a kit made for BOTH the 9.9 and 15hp as parts are identical. Its literally a known configuration as both motors have identical parts.

 

[kalebg]

You know ive made 0 mention of a high speed adjustment. I actually re clarified this fact and you still seem to have not read it. But again that requires you have the intelligence of being capable of reading a full reply.

 

[racerone]

Good luck with your motor.

 

[kalebg]

You know ive gotten: oh no dont worry, oh its okay, and the obvious indication you know nothing and about running lean and engine operation. If you knew your head from your butt youd tell me to: pull my plugs, clean them, reinstall and run for a bit, then pull plugs and read then to tell if im running a little overly rich or lean, but I dont think youd even know how to read a plug

 

[racerone]

I have several of these 9.9 / 15 hp motors !-----Take your motor apart , every nut & bolt.----Even throw in a few extra parts if you like.----Bring it over and I put it together without a glance at a manual !

 

[oldboat1]

Replace the impeller annually if still in salt, and monitor cooling with an IR gun (top of head). 50:1 oil mix. Shop around for a 9.9 carb with standard 9.9 jet -- likely a little better operation.

 

[Tim Frank]

Its not a franken carb. Its literally a 15hp carb of a 15hp evinrude . So untouched it still had the original cork float and rebuilt with a kit made for BOTH the 9.9 and 15hp as parts are identical. Its literally a known configuration as both motors have identical parts.

Both motors have MANY Identical parts....not ALL..
if you check the archives in here you will find MANY threads of guys who tried to mix parts from the 9.9 and 15hp either trying to create a 15 from a 9.9 or just to save a buck.
I have yet to see one that really worked.

You are getting really testy because people are not getting some of your descriptions and narrative....even questioning their reading skills and intelligence
I could be wrong, but that might reduce the responder pool; maybe think about upping your writing skills and provide more details.

You started the thread by explaining that you are not very knowledgeable about 2 strokes....then proceeded to write volumes of theory about all kinds of topics that are not really relevent.

You said that you have several parts motors as donors....and called what you are building a frankenmotor.
If you actually know the provenance of them all, fine. If not, you cannot assume any part is actually correct....including the carb.

The fact remains that a 15hp carb was not OEM on a 9.9 HP.
If you are 100% certain that it is a 15 hp carb from the same year and has never been tampered with, just say that, instead of
getting your shorts in a twist because none of us are mindreaders, and we are getting little enough to go on despite your pride in your narrative to date.

 

[kalebg]

Tim go ahead for a 1975 9.9 hp and 15hp and find the parts list because i already have. The manifold is the same, the reed plate is the same, the reeds are the same, the carnkcase is the same, the head is the same, the crank is the same, the pistons are the same, the ignition plate is the same, the ignition coil is the same, and even the exhaiust is the same.Tim Im just not understanding why the first assumption is that the least likely scenario that the carb was modified when I made 0 indication of the fact. The lean operation is very relevant to a motors operation and someones lack of understanding and possibly having new people eventually damage their engines causing thousands in damages is frustrating. Learn a little more about motors is a must. A motor can run lean simply put, its only incapable of running lean if it is fuel starved. You know AFR 14.7:1 stoic and leaner mixes can run, just excess heat or very lean might have issues running at all. Or me to ask and detail a possible issue with fuel priming a possible cause and someone to read half of it and think im adjust high speed jet with low speed knob and ask have you checked your fuel system. Like no s***t literally just said a possible issue not to mention Oldbaot1 at least gets whats going on already

 

[Tim Frank]

Unfortunately there is no way for me to post in crayons and use large printed letters and illustrations. I really am getting the impression that is what it would take to get the message through.

The irrelevent info and pics about various piston damage is taken from air-cooled two strokes operating at 10k plus rpm.
Run your water o/b at that speed and you might have a point....but probably not a motor.

The carb from a 1975 9.9hp.....that you said is most of what you have built.....is different from a carb for a 1975 15hp.
You still have not confirmed that you know without doubt that your parts carb is from a 1975 15 hp. And that the 0revious owner did not get creative.

In any case..the OEM carb is different and the high speed jet is different....and according to your posts, you are having carb related problems.
I will let you connect the dots....

 

[kalebg]

Lean Fuel Mixture


A common cause of overheated pistons relates to insufficient fuel delivery to the cylinder to keep the temperature down. Idle mixture screws that have settings which are too lean will cause a lean air/fuel mixture, and too much air in the combustion chamber causes the temperature to rise. Kinked fuel lines and clogged fuel filters will also starve the cylinders. A rich, or wetter mixture counteracts the condition.
https://itstillruns.com/causes-up-pi...r-8669199.html

This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information

Truth is you dont know your a** from a hole in the ground bud

 

[kalebg]

Also if the entire engine is verifiably the same part by part with the only difference being the model plate and the carb you do the math. That model plate doesn't make the carb incompatable