1997 carbuerated 200 Yamaha 2 stroke

[bondobill]

Been noticing lately when out fishing the Yamaha doesn't want to start very well when it has been turned off for a hour or so
Tryed choking it and it wouldn't start at all
It will start but dies three or four times before it will keep running
First start in the morning it fires up just fine by choking it but runs a little rough at idle before it warms
Pulled the hood today and fired it up, thought I would turn up the idle a little
When I fired it up with the hood off I heard this intermittent blast of air and motor would cough at the same time


Found these 2 hoses that run from the reed valve body going no where. The blast of air I was hearing was coming from them


I can see where they are supposed to attach at the block
Nipple is at center of photo

I tried hooking them up but as soon as I started motor they blew off
I can't see that they ever had clamps on the hoses
Are there supposed to be clamps holding them on or to I have other issues creating too much pressure.
Motor runs awesome except for the issue of stumbling at idle till it warms up

[fitz73222]

Hi Bill,
This is a good one for Loye (futch13). I know he knows the bleed system on this engine. Some of these nipples have check valves behind them and may require removal of the intake to replace them, but since I'm not sure about this engine, discount that remark until we can verify. Depending on what the hose is actually doing, some are clamped and some are not. Throw a zip tie on them and try running again, see if the idle quality changes. So as long as the engine doesn't have a constant cough at idle, it shouldn't be something as serious as a reed valve causing the backfeed plus you don't have any performance issues off idle correct?

[bondobill]

Thanks Fitz
I was hoping you would chime in
Except for it wanting to die a few times at idle after starting when it cold she purrs like a kitten

Only thing I have noticed is the engine always started instantly before.
If it was turned off for a couple hours or so when we where out on the water I could hit the key with out choking and she would fire right up. She would run at around 1200 to1400 rpms for a second or two then she would drop down to 700 rpms and idle smooth.
It doesn't do that now unless the engine is still warm.

I never noticed those 2 hoses just hanging there before today. They got a pretty good burst of air coming out of them, you really can hear it with the motor running and the hood off.
Maybe the shop that serviced the engine last spring forgot to hook them back up.
Didn't have any starting issues last summer but maybe its got something to do with the colder temps this winter.

I'll pull it out tomorrow morn......before the Super Bowl  ...... put some ties to the hoses and see what happens then.

Thanks man

"Go Hawks"

[fitz73222]

Hi Bill,
I sent a PM to Loye to see if he has a solution.

[futch13]

Bill,  The nipple the hoses keep falling off of are check valves.  They seem to be working as pressure is building up in the hose.  Probably the nipple where the hose is still connected is clogged causing the pressure to build up in the hose and blowing off the check valve.  Try running a small wire or fishing line thru the nipple to see if clogged and then blow it out with air.  There are no clamps on those hoses from factory so replace them as they may be "worn out" and not gripping the nipple properly.

[bondobill]

 Thanks Loye and Farly
Took your advice and ran a  wire through the nipple
Blew some air through the lines and also replaced the tubing.

A lot tighter fit to the nipples with the new hoses

Going pull it out of the shop here shortly and will let you know the outcome

Would those hoses disconnected affect the idle ?

Thanks guys

[futch13]

Yes, the intake side will make those cyls run lean.  Will be especially noticeable when cold.

[bondobill]

You got to love a .85 cent  fix on a o/b
Pulled boat out of shop and fired her up........

Idles awesome  hoses stayed in place

Loye you scared me a little about those cylinders running lean so I took a compression test after engine was warm......all cylinders between 115-120.
Same readings the Yamy dealer had last spring

I can't thank you and Farly enough   

Now I can focus on the game   

[fitz73222]

Priceless!

[futch13]

Glad to hear!!!!