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HELP RX1 cold start issues

ballbuster

Newbie
Joined
Apr 3, 2015
Messages
12
Age
43
Location
Massachusetts
Country
USA
Snowmobile
Nytro, F7, Vmax 540, SS25, 1100 MXZ
A friend of mine has a 2003 Yamaha RX1 and it takes forever to start it when cold and sometimes it just won't start. Once I get it running and warmed up it starts right up. The choke does work because when I flip it on when running it will change the idle. I have cleaned the carbs 3 times and it hasn't helped at all. The carbs are spotless. I ran a small copper wire through all the jets. I have checked the TPS and it's within specs according to Yamaha. I have also cleaned the TPS with electronic cleaner. I put a new set of stock plugs in it and just changed the oil. The sled does have high miles right around 8000. It runs fine when it's up and running. Do you think the sled would need a valve adjustment and would this have anything to do with cold start issues. I crank it over for a while and if lucky it will pop a couple times and slowly get running. I have checked the spark and it seems decent. I have even used starting fluid and it just doesn't fire right up. Any help would be great. Thanks.
 

If you apply the choke while its running right it should kill it almost instantly. I'd say make sure choke cable it tight enough. Its easy to mess up when removing the carb rack.
 
Yes it will kill the motor if you turn it on at all. If you're quick you can just hit it a little and it brings the idle down before stalling it. I checked the choke pull and when the choke is off the plungers are closed. Pull the choke out and you can see all 4 plungers pull out. It's driving me crazy.
 
Yes it will kill the motor if you turn it on at all. If you're quick you can just hit it a little and it brings the idle down before stalling it. I checked the choke pull and when the choke is off the plungers are closed. Pull the choke out and you can see all 4 plungers pull out. It's driving me crazy.
8K is not high miles on that engine, but your right I've never had a issue like your's gotta be fuel or electrical, best thing is if it does it all the time then you can figure it out. I would do a compression check just to take that out of issue-and check coil's.
 
might be the check valves in the fuel pumps are bad. have you tried blowing into the fuel tank vent line while cranking to see if it starts better?
 
A friend of mine has a 2003 Yamaha RX1 and it takes forever to start it when cold and sometimes it just won't start. Once I get it running and warmed up it starts right up. The choke does work because when I flip it on when running it will change the idle. I have cleaned the carbs 3 times and it hasn't helped at all. The carbs are spotless. I ran a small copper wire through all the jets. I have checked the TPS and it's within specs according to Yamaha. I have also cleaned the TPS with electronic cleaner. I put a new set of stock plugs in it and just changed the oil. The sled does have high miles right around 8000. It runs fine when it's up and running. Do you think the sled would need a valve adjustment and would this have anything to do with cold start issues. I crank it over for a while and if lucky it will pop a couple times and slowly get running. I have checked the spark and it seems decent. I have even used starting fluid and it just doesn't fire right up. Any help would be great. Thanks.
How old is the battery? I had a similar situation with my 03 where it would crank at what seemed a normal speed but not start. The battery would run down and I knew it would just kill the battery dead if I continued. It would always fire right up when I got a boost from my friends Apex. I ended up replacing the battery and it starts better than ever. I think that late in the life of a battery that the voltage drop when cranking is just too low to fire the coils. Try boosting with another battery before your first try at starting to test this out. Also clean the ground connection where it attaches to the block.
 
My wife's warrior is this way I drilled a small hole in the side of the air box and plugged the hole with a plastic expandable tee nut Then when its really cold I pull the plastic tee and give it a shot of carb cleaner Works Great
 
How cold? My 05 when it gets down to -30 to -40 needed you to just barely open the throttle a hair. Would fire right up. Otherwise it just sounded like it was trying to start with no success.
 
Hard to trouble shoot from a keyboard but plugs and or plug gap can cause hard starting ( you put in new plugs and gaped correctly so can rule them out) as well as weak or dirty coils. Kinda reiterating whats said but here goes!

On my 05 I cleaned my coils where they connect to the plugs every year. They would be full of black carbon and where a cause of hard starting, there are little wire clips inside the coils that slip over the threaded end of the plugs. They can be worn or even missing. Because the coils just sit on top of the plugs and vibrate like crazy unlike the Later Apex that is bolted down and vibrates less they wear more. Clean and check! If you look at the coils in the dark when sled is running you will probably see quite a light show. That show is wasted spark. Dirty coils/bad connections = bigger light show.

One other thing is compression, low compression will make an engine very hard to start. Slow cranking will as well from a weak battery or a starter that maybe drawing too much juice to turn over and beside cranking slower its also not leaving enough power to fire the coils at full spark.

All I can think of that might help, wish you luck finding the gremlin! I hate gremlins!
 
If it doesn't fire up.right away using starting fluid it is most.likely a electric problem... But if you no gas in the cylinder it will take the starting fluid a second to fire off as well... the next time you try and if doesn't fire up take out the plugs and see if they are wet or not... If they are not wet you have fuel delivery problem... if they are wet you have a weak spark...
 
Having the same issue with my 03. Carbs have been off 5 times now every orifice is spotless. Before I reinstalled the rack i blew into the fuel lines and tipped the rack to make sure the needle and seat were working properly. Fuel pump is putting out steady fuel. New plugs. Fresh oil change. When I bought it however 2 of 4 heater assemblies were broken off. Just came in from trying again and I see that I have fuel pooled up in the carb.
 
Having the same issue with my 03. Carbs have been off 5 times now every orifice is spotless. Before I reinstalled the rack i blew into the fuel lines and tipped the rack to make sure the needle and seat were working properly. Fuel pump is putting out steady fuel. New plugs. Fresh oil change. When I bought it however 2 of 4 heater assemblies were broken off. Just came in from trying again and I see that I have fuel pooled up in the carb.
How many miles on it?
 
10,378. Bought it drove it onto my trailer this summer and put it in the garage. Ran fine but I wanted to make sure that the carbs were clean like I do on my other sleds.
 


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