Yamaha 2stroke question

glacierbaze

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Boslaw, not knowing that the push button on your throttle was to disengage the shifter means that you have never tried to start your engine at any rpm other than idle. That opens up a whole 'nuther world of possibilities.
You need to take the cowling off the engine, tilt it up and turn to one side , so that you can see the linkage from the helm, and learn what the hell is happening back there. I have had the same set up on a '93 200hp for 10 years, and have never touched the manual choke on the motor. When you lift the electric choke/toggle switch, the choke plates slam fully shut, it's all or nothing, and you can see and hear them. To say that the manual choke is more aggressive is just wrong.
Pump up the fuel bulb, push in the shifter release button, pump the throttle a couple of times, and go back to neutral. Turn the key with one hand, and with the other, lift the momentary toggle/electric choke for a second or two, and see if it fires. If it starts and idles like it wants to stall, give the choke toggle a quick lift and release, and it will rev up. You may have to do that a couple of times until it warms enough to idle.
You can also try to start with the throttle advanced, just be timid to start with, or you will fire up at 5000 rpms.
A question, what are you doing during the 30 minute interval which precedes the engine not restarting? Mainly, are you consuming voltage during that time. Yamahas don't start on low voltage, although they will crank. Look at the voltage read out on your GPS when you shut the engine off, and before you try to restart 30-60 minutes later. If the engine doesn't fire right away, try switching the batteries to "BOTH".
My motor might take 10 seconds of fiddling with choke and throttle, if it has been sitting for a week or more, but after the first crank of the day, it will start faster than you can release the ignition key, with no choke. That's a motor that has not had one thing done to it in over ten years, other than bolt ons, like starter, impeller, LP pump, etc.
 
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seasick

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Had same issue my mechanic told me to put it in neutral and give it some gas and then start it worked for me
This is interesting comment in a way.
Let's say that the throttle is closed all the way for some odd reason when the motor is hot. That would starve the motor for air. Of course, I would expect the opposite, that the throttle is closed when the motor is cold.
I still dont understand but trying to start by pressing the shift override button and advancing the throttle level will open the throttle plates if they are closed too far.
 

seasick

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I think he said that it would restart when it was hot, in that first 15 minutes. It's that 15 to 60 minute window that is problematic.
Then maybe the choke is re-engaging when the motor is still too warm to need it. I am going to look for a service manual to see if there is anything on how the electric choke works.
 

enfish

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Then maybe the choke is re-engaging when the motor is still too warm to need it. I am going to look for a service manual to see if there is anything on how the electric choke works.
Or the opposite... it's not engaging when it needs it. But I think a lot of his issues will go away if he tries starting with the throttle advanced.
 

seasick

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I found a file of the service manual for the S200 motor ( not the SX).
There is a part called the fuel enhancement valve that seems to have two wires connecting and I think a shaft that is part of a solenoid. I guess the shaft moves something mechanical in the throttle linkage or carb linkage.
The only sensor that mat affect the decision to change the mixture is the thermo sensor ( not the same thing as the thermo switch )
The fuel enrichment valve coil should read about 3 to 4 ohms (disconnect the connector to test)

I also found out that bad reed valves can cause low and/or rough idle but to be honest, that is not an area you want to get into).
I was unable to find test plan for the operation of the enrichment valve so I don't know what makes it work and when.

The S200 motor does not have the ability to connect to the Yamaha Diagnostic System. It has only the capability to use the winky blinky test lamp. There are possible codes for enrichment valve failure as well as thermosensor failure.

Note that error codes are not stored in these motors. They only display when the alarm is active. I would assume that the enrichment valve could fail in two different ways; electrically where it doesn't activate or mechanically where the signal is there but the push rod (solenoid shaft) either doesn't extend or maybe retract. or gets stuck when moving.

Do I think that valve is your problem? I have no idea:)
 
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Topjimmy

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The rubber circle on the throttle arm is the button that disengages the shift cable so you can advance the throttle in neutral. Push and hold it in while pushing the throttle lever forward and you'll stay in neutral and be able to start the motor with the throttle advanced.
Yep OnoEric is right also in 27 years of owing my 94 Grady with a 150 Saltwater I have NEVER used the manual choke on the motor only the toggle switch next to the key that is all you should need to do and Yes for me running 91 Octane helps it idle smoother and do check the 2 LP Pumps I have had them go bad more than a few times
 
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Doc Stressor

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For the first time, I just read this thread and recall all the finicky carbed 2-stroke engines I've had to deal with over the years. I've never been able to figure out the source of the vapor lock that was so common during the summer. It's either in the fuel system or the carburetor bowls themselves. In most cases, the hot start problems would minimize when they switched to summer-blend fuel later in the season. Anyway, I always just advanced the throttle in neutral to get the hot engine to start. As soon as it fired up I would reduce the throttle to the idle position and it would run fine. Each engine pretty much had its own ideal hot start throttle position.

I got pretty used to doing this, so I never understood the need for fuel-injected engines. Until I finally got one. :)
 
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seasick

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For the first time, I just read this thread and recall all the finicky carbed 2-stroke engines I've had to deal with over the years. I've never been able to figure out the source of the vapor lock that was so common during the summer. It's either in the fuel system or the carburetor bowls themselves. In most cases, the hot start problems would minimize when they switched to summer-blend fuel later in the season. Anyway, I always just advanced the throttle in neutral to get the hot engine to start. As soon as it fired up I would reduce the throttle to the idle position and it would run fine. Each engine pretty much had its own ideal hot start throttle position.

I got pretty used to doing this, so I never understood the need for fuel-injected engines. Until I finally got one. :)
I have fuel injection on my Yami SX and I don't have a lot of experience with the carbed models.
What I have learned in the last hour is that I completely misunderstood how the fuel enhance feature works on a YAMI. ( Yes, ignorance is bliss)
Whether or not that valve can explain the hot start issue is not clear. A faulty enhancement valve can explain cold start issues. The valve works by heating up its coil. That causes a fuel needed to extend and that reduces fuel flow. In other words, when cold the system makes the mixture rich and as the coil heats up, the mixture gets leaner.
Here is a link to a video from a person who's videos in general are quite informative and entertaining.

I still have no idea if this valve is related to the warm start issue with the possible exception that the motor cools faster than the enrichment valve (or the needle sticks when hot) and when trying to restart after a while, the motor needs a rich mixture but the enhancement valve is still in lean position.

It is also possible that the above referenced Prime Start valve is completely different from the Fuel Enhancement Valve listed for the S200. I am just grabbing at straws right now
 

boslaw

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>>>Boslaw, not knowing that the push button on your throttle was to disengage the shifter means that you have never tried to start your engine at any rpm other than idle. That opens up a whole 'nuther world of possibilities.
Sorry for disappearing for a few weeks. I had some family stuff last weekend so I wasn't able to get out to the boat. Gonna try some of these suggestions this weekend (especially the above, which should be simplest) and report back.

Part of my confusion about giving gas while starting in neutral is that under any other circumstance, you can't start the motor at all if the shifter is out of the neutral position. It just never occurred to me that I could push the button to move the shifter while remaining in neutral and actually start 'er up.

 

boslaw

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After a day at the beach today, I started with the shifter engaged- started up immediately. Love learning something new about my boat. For the first 10+ years I had the boat/motor it would always start right up. Guess it's gotten a little finicky in its old age. Hopefully that was the answer to my problem.

Thanks to all for the many suggestions. I'll know where to look if I continue to have trouble.