Few Little Problems....

Yamaha_Chuck

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Mar 18, 2011
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Location
Keswick Ridge, N.B.
Well I finally got my sled running fairly well, it was an issue with the power valves that is now resolved. However I still have a few issues. The first issue is the cold start which I have read a lot on about here, but mine is getting plenty of fuel in the cylinders as it is soaking the plugs and you can smell the gas.....only way to get going is to add fuel down the cylinders.
The other issue is an idle issue which might be related to the starting issue, not sure. After it warms up it idles at a steady RPM but make a strange backfire, almost like a poof sound, not a bang.
And lastly, from a dead stop, when I punch it, it will almost die out. Other than these problems it works A1 out on the trail and pulls strong. Any advice would be great. Could it be the fuel screws not set right?
 

If you have to add fuel into the cylinder to get it to start it is not getting the proper amount of fuel! Clean the carbs. The pilot jets are likely plugged.
 
If you have to add fuel into the cylinder to get it to start it is not getting the proper amount of fuel! Clean the carbs. The pilot jets are likely plugged.
Its defiantly getting fuel because like I said, you can smell it and plugs are wet....IDK, maybe too much fuel but it doesn't even kick. And I forgot to mention, had the carbs off twice and they are spotless. I followed the step by step procedure on here.
 
mine is getting plenty of fuel in the cylinders as it is soaking the plugs and you can smell the gas

only way to get going is to add fuel down the cylinders.

These 2 statements are in the same sentence and totally contradict each other. If the only way to get it to start is to add fuel then you are not getting enough fuel which would lead to Jabbers thought of the pilots
 
These 2 statements are in the same sentence and totally contradict each other. If the only way to get it to start is to add fuel then you are not getting enough fuel which would lead to Jabbers thought of the pilots
Yea I was expecting someone to say this and I know it doesn't make any sense. I even had someone else look at it and disassemble the carbs after I did it (a Yamaha tech actually) so the carbs are spotless. This sled has made me scratch my head a few times. If I get some time tonight I will take a video and try to upload it
 
What are the fuel screws set at? They are part of the pilot circuit so if they were in too far they could be the issue
The last time they were apart I had the mechanic do it so I assume they are set to factory specs but it would be an easy thing to play around with. Would it be possible to adjust them just by pulling the air box?
 
Wet with oil would/could look like wet with gas and may even smell like gas. Ever try hitting this wet plug with a lighter? If its enough gas it will light right up...wet with oil wont do much. PLEASE do not be offended by this next statement, only mentioning it as I have heard of guys that didn't know. Are you flipping choke lever all the way almost flipping it over backwards? Choke has start and warm position. Only other thing I can add is look at the choke plunger as you are working the lever. Make sure all 3 are moving and are full choke. Plungers should move pretty near as soon as your moving lever, with it in full choke reach down there with your finger and see how much further the plunger will go.
 
That's a good idea with regards to the plugs....will check it that way for sure. And no I'm not offended by your comment.....I know you cannot hear or see any of my problems. The choke is adjusted properly and working as it should, it can die out the engine when warmed up and I can see the plunger rods moving in and out. I have read on here that it helps cold starts to kill the engine by choking it so that's what I did yesterday. We have a big ride planned for Sunday so I will let it sit until then.
 
I didn't see your previous question about the fuel screws prior to my previous post. Seems like it would be a major PITA to adjust fuel screws with them still in sled. Some guys have the "remote adjusters" that I have thought about making per the how to write up rather than buy a factory made set.
 
If the motor has compression and spark and you add fuel to the cylinder and it starts your problem is fueling! When cleaning the carbs did this tech use compressed air and blow out all the jet passages in the carbs when the jets where removed? Could the wrong jets have been put into these carbs? With a cold engine choking or fuel enrichment circuits increase the fuel to air ratio to make starting easier. Even though you smell fuel it does not nessisarily mean there is enought to make cold starting easy. Does the engine start ok after warmed up?
 
Yes it starts A1 when warmed up. I tried it last night after work (it was cold) and it started but cranked over for about 5 seconds before coming to life but I did have to baby it for the first few minuets with the choke to keep it running. It was sitting in my garage but the other day it had been sitting on back of my truck when I couldn't get it to start....was colder that day too.
 
It's a pain to get at but check the fuel filter in the gas tank too,you might have an issue there,possibly plugged up or getting to that point.Perhaps the line in the tank might be split?I'm just throwing out ideas but if it were me I'd start at one end and go right through each and every part to eliminate it as a possible cause.
 


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