2000 Yamaha 9.9 2 stroke won't start

[SeaRogue]

Hi all,

long time browser, first time poster, I'm not a mechanic, but have experience with cleaning carbs, compression tests, spark checks, the basics for these engines.

Purchased a non-starting 2000 Yamaha 9.9 2 stroke, looks like its in very good shape. Current status is not starting. Compression is 130 on both cylinders, white/blue spark on both plugs, and carb has been cleaned, fuel gets to the fuel bulb and primer stays hard. Exhaust also is unblocked. Spark plugs consistently appear dry, and have not smelt of fuel. I don't believe fuel is making it to the spark plugs.

The confusing part to me.. is it won't start, pop, anything, fuel sprayed down the carb body does nothing, fuel (very small amount) deposited in the combustion chambers causes a sputter. I have held a small piece of fabric in front of the carb intake, the reed valve intake, and the crank case intake (removing successive components to do this). The fabric shows no indication of air flow, and barely flutters, almost looks like its being pushed out.

This leads me to believe that the crankcase has a serious leak in it, as the combustion chambers are pulling enough air in to build the compression, but not from the carb body.

Go easy on my brain, I have a difficult time retaining motor concepts, but stupidly enough, enjoy getting my hands dirty....

Mark

 

[QBhoy]

Hi. At the risk of being cheeky, is the fuel line gpimg from the tank to the engine the right way around ? The bulb will only go one way in direction of fuel between the two.
ive had and still have a number of small Yamaha 2 strokes similar. There is definitely a technique to starting them easily too.
Even if I leave mine for years without startimg…fresh fuel primed through the carb…pull choke on with a little bit of throttle…pull on her a couple of times and she will give a kick. Choke off and open the throttle and catch on the throttle as she starts. Works every time.
Anyway..if you aren’t getting that far, like you say…definitely look towards the fuel line and it getting fuel. Prove its getting fuel by cracking open the small drain screw on the bottom of the carb and pump the priming bulb to make sure there is a flow of fuel coming out there. If you aren’t…you have a blockage somewhere or you have the fuel line and primer bulb going the wrong way. Easily done.

 

[SeaRogue]

Hi QBhoy, thanks for the reply,

Its not cheeky, and something I have checked multiple times to make sure it wasn't a simple oversight as that. I can pump the fuel into the carb., and the primer bulb hardens and stays that way (Verified by draining carb), and the jets are clear. (Checked multiple times). I do not seem to be getting air through the carb, I am assuming (as I have never needed to check this before) that a simple tell tale in the carb intake should suffice to demonstrate air being pulled in.

My current thought is that the crank case has a leak in it, allowing air to be pulled in from somewhere besides the carb, but I do not know enough about this to know what to check. I am hoping it's something simple, please keep it coming!

Mark

 

[99yam40]

Being this motor is a 2 cylinder, it would be strange to have both the top and bottom crank seals to go at the same time, but it might happen.
there is also a seal between the 2 cylinder crankcases.

not knowing what all has happened or done to a motor makes it hard to figure out some problems.
could someone have taken it apart and not put it back together correctly, gaskets/seals etc?

 

[Sea Rider]

Being a 21 yer oldie, have you checked the spark plug's intensity with a tester, the ones that can vary their spark gap lenght ? Meanwhile remove both plugs, squirt a small dose of pre mixed fuel inside each cylinder with a small syringe, put plugs back in and crank the motor at full open throtle to check if the mixture ignites well or not.

Happy Boating​

 

[SeaRogue]

Update on this motor, today I pulled apart the crank case after removing the power head. The top bearing sounds likes its shot, the center bearing between the two pistons sounds fine, however, the seal? right below that is loose and has a torn part sticking out of. Can someone enlighten me as to what the seal does? I'm assuming I need to replace this piece. Or maybe its not a big deal. Quick checks on Crowley Marine indicates I can't get the individual part, and will have to order the entire crank case. In which case I'll probably just sell the motor off for parts.

Finger indicates the loose part.

Mark

 

[99yam40]

you can have the crankshaft rebuilt.
just have to find a machine shop that can do it
I sent my C40TLRX crank to a shop in NC

 

[Sea Rider]

As you have witnessed outside mint condition motor doesn't say much, can be buying blindly a Pandora Motor without knowing. Seems the crankshaft suffered from poor lubrication or the motor went diving, was drained, cleaned and stored. Will need to open and rebuild the entire crankshaft as suggested or buy a complete seconh hand one in good state, what's the cylinders and pistons condition ?

Happy Boating​

 

[SeaRogue]

As you have witnessed outside mint condition motor doesn't say much, can be buying blindly a Pandora Motor without knowing. Seems the crankshaft suffered from poor lubrication or the motor went diving, was drained, cleaned and stored. Will need to open and rebuild the entire crankshaft as suggested or buy a complete seconh hand one in good state, what's the cylinders and pistons condition ?

Happy Boating​

Thoughts on what you said would be that if the crank case suffered an air leak, then the motor would have been running lean - leaner - dead. I'm going to take the crankshaft into a local marine mechanic to get an opinion, and an idea on what it will cost to rebuild. Here's some more pictures, piston heads, and both combustion chambers.

 

[99yam40]

find out where they send cranks to be rebuilt, and then talk to them about what the cost of reworking a crank would cost.
if you ask what the marine tech would charge to rebuild the motor for you, I am sure you would not want to pay that

 

[Sea Rider]

For me that motor suffered an overheat from poor lubrication, have seen such scenario before. What need to do is tear the whole pressed crankshaft at a machine shop and check what needs to be changed as the damaged parts are non repairable. Can get by with both connecting rods, but will need to install new small needle bearings and large ball bearings, but if the crank pins which holds the other crankshaft's parts together are shot and are NLA better get a second hand complete crankshaft.

Happy Boating​

 

[SeaRogue]

Two questions, first will show my experience level...

For me that motor suffered an overheat from poor lubrication, have seen such scenario before. What need to do is tear the whole pressed crankshaft at a machine shop and check what needs to be changed as the damaged parts are non repairable. Can get by with both connecting rods, but will need to install new small needle bearings and large ball bearings, but if the crank pins which holds the other crankshaft's parts together are shot and are NLA better get a second hand complete crankshaft.

Happy Boating​

Two questions, first will show my experience level, haha, what are you seeing that tells you this motor overheated or went for a dive?

Second question is, when purchasing a used motor that isn't running, is there something to watch for to prevent a repeat of a bad buy...

 

[Sea Rider]

Two short answers :

1-The whole crankshaft is way discolored, brownish look, to check if dived in salted water, put your tongue at several parts and check if salted, which will indicate that the motor dived which it's the worse case scenario.

2-With second hand motors won't know if won the Lotto or purchased a Pandora Motor, all sellers swears that their motors are in excellent shape to find out that once payed for was a different scenario.

Anyway if dived or not or suffered from poor lubrication will need to reconstruct the whole crankshaft or buy a second hand one....

Happy Boating​

 

[Faztbullet]

That motor/crankshaft has NO signs of overheat or water ingestion. The beer bottle brown color you see is from additives in gasoline from the gas pump. The additives bake out under heat of engine running. The seal separates the 2 cylinders from each other. You call a Yammy jet ski dealer an find out who remans their cranks on rebuilds

 

[Sea Rider]

That motor/crankshaft has NO signs of overheat or water ingestion. The beer bottle brown color you see is from additives in gasoline from the gas pump.

Really ? You don't even believe what posted yourself. So the fuel additives shot the middle tough ball bearing, wow what a great high tech explanation with usual out of this world comparissons. It's a 2 stroke Yam 9.9 motor, what has to do with a Jet Ski which runs at constant full fun max wot rpm range ?

Let the OP state with tongue method if said motor went diving in salt water as a starter and avoid wild guessing. That motor was bough shot right from the beginning and the seller washed his hands as Pontious....

Happy Boating​

 

[Faztbullet]

SeaRider...As usual your inexperience and understanding on 2 stroke engine internals shows up again. If it got hot the rubber parts externally and internally would be melted or crispy, Also the pistons would be scuffed 360°. The discoloring is not from heat or rust. The middle bearing seal is swollen from possible ethanol damage The owner states the middle bearing is smooth not shot. What it has to do with a Yammy jet? It is is how crank is put together and sealed. Here is a Yammy 500 crank....pretty dang similar. SeaRogue the part # for seal is 63V-11515-01-00 and if you find a rebuilder they can replace it.

 

[99yam40]

I agree with the crank not being discolored, looks like a normal crank and rod color.
and the OP said the middle bearing sounds just fine, not sure why you call it "shot the middle tough ball bearing"

 

[Sea Rider]

Whatsappmatter with you FB, Wrong again, to make it short as I'm undergoing full restorations on 2, 2 stroke motors, one being my beloved 18 HP which has clocked 1,050 run hours and needs to be fully recovered asap. Your post is the furthest thing from reality due to lightly reading what the OP posted, not using your eye wear to capture details which says it all or beginning to have mental gaps between what you read and post...

To clarify, we're dealing with a 2 stroke Yam 2000/9.9 which crankshaft's employs 3 ball industrial bearings, no middle seal whatsoever to be replaced, so flew high on this one. That shows how "expert" you are comparing crankshafts that doesn't match at all. Guess what, already mentioned being a pressed in crankshaft typical of japanese motors.



The crankshaft's pic clearly shows the middle bearing's pointed with finger showing upper track being already disassembled from the lower track which indicates a shot bearing due to ? That boat/motor combo was sold as a package in order to get rid of it fast and have a much better selling price under the modality of where it is and how is it. A clever move.



Check this resized pic, the crankshaft looks discolored and shows sign of rust, oxidation at both connecting rods along parts marked with a yellow * and the pistons look slightly scuffed, and that ain't nothing to do with E fuels to be blamed for, if that were the case both remaining ball beaning along 50 connecting rod's pin dowels (needle bearings) would have gone that way and are seen intact.

If hard to accept what posted as you're a professional denier regarding my posts, check both pic on a PC, notebook, cellphone than can be hoked to a large 50" monitor and check both described scenarios. Nope with a **** Tracy wristwatch, nano cellphone won't be possible to check that out.

Can't possibly know by pure vision if a needle or ball bearing is shot, for that will need to properly lube it, spin it hard and check by ear sound is revs smooth or with issues.

To finish, the connecting rods color seen on post 16 has nothing to do with what post 6 and 9-3 shows, who are you trying to cheat, seen that scenario before so to speak with reason. Bottom line, get a complete new crankshaft that sells for around $ 700 bucks at : https://www.boats.net/product/yamaha/63V-11400-00-00?ref=3432c235aca43de38ae19609165419498fa40eb3 or buy a second hand one in opt state for way less, you decide...

Happy Boating





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[Faztbullet]

Sea...how can I say this nicely?? Your a idiot and have no idea what your talking about I guess is the best way, That bearing has nothing wrong with it as that is a seal (called labyrinth seal ) and sets in the groove milled into crankcase. I supplied the part number for replacement. Funny the areas you claim are rusted are rough castings but milled ends of crank throws and bearing races are shiny....guess rust only attacks certain areas.. Yes the pistons are lightly scuffed but thats not from overheat as there is no aluminum transfer, more likely a lean fuel oil mix. This is what your looking at below bearing....

"""To clarify, we're dealing with a 2 stroke Yam 2000/9.9 which crankshaft's employs 3 ball industrial bearings, no middle seal whatsoever to be replaced, so flew high on this one. That shows how "expert" you are comparing crankshafts that doesn't match at all. Guess what, already mentioned being a pressed in crankshaft typical of japanese motors.""" .... SeaRider this statement shows how much you dont know. The Yamaha 500 crank has 3 bearings and seal in a housing.. So this operating design is just like the OP's 9.9 so they match pretty dang well. There is your lesson for today......duh

 

[99yam40]

Searider, did you even read what the OP wrote?

The top bearing sounds likes its shot, the center bearing between the two pistons sounds fine,

also how do you expect the two crankcases to seal off from each other if there is no seal between them like you posted.
how do you expect anyone to take you seriously when you post things like this?