Need to figure out my 02 SRX 700 hard starting!

yamisrx

yamisrx

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Aug 21, 2022
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I've made it my goal to get my 02 SRX 700 to be a better starter before winter this season. The problem is if it sits for a few days or more it takes 40-50 pulls to start. It also does similar if its extra cold out. I've been through and cleaned the carbs, added new oem yamaha reeds, went to a 45 pilot jet from the stock 42.5, and turned fuel screws to 1 1/2 turns out. I've checked compression and all three cylinders are at 130 psi. I've added a new vmax sx fuel pump to eliminate the vent on the stock pump and also a petcock valve in between the tank and pump. None of this has helped. Once the snowmobile has started and it's warmed up it starts first pull every time. If I put a little premix gas down the cylinders it starts first pull but who wants to do that constantly? I have also done the choke off untill it dies method and if it's within a few days it will start first pull also. Anything I'm missing? If there is nothing else I'm thinking of adding a primer to it.

Thanks
Greg
 

yamisrx said:
I've made it my goal to get my 02 SRX 700 to be a better starter before winter this season. The problem is if it sits for a few days or more it takes 40-50 pulls to start. It also does similar if its extra cold out. I've been through and cleaned the carbs, added new oem yamaha reeds, went to a 45 pilot jet from the stock 42.5, and turned fuel screws to 1 1/2 turns out. I've checked compression and all three cylinders are at 130 psi. I've added a new vmax sx fuel pump to eliminate the vent on the stock pump and also a petcock valve in between the tank and pump. None of this has helped. Once the snowmobile has started and it's warmed up it starts first pull every time. If I put a little premix gas down the cylinders it starts first pull but who wants to do that constantly? I have also done the choke off untill it dies method and if it's within a few days it will start first pull also. Anything I'm missing? If there is nothing else I'm thinking of adding a primer to it.

Thanks
Greg
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Seems like a lot of pulls. I could see 15-20 pulls after it sits for a week or 2 but after a few days should start in 4-5 pulls.. I would try and rebuild the fuel pump, maybe its not pushing fuel fast enough or the vaccum that moves the diapram in the fuel pump is not good from the motor. Could check lines or change lines and make sure they are clamped tight..
 
MrSled said:
Seems like a lot of pulls. I could see 15-20 pulls after it sits for a week or 2 but after a few days should start in 4-5 pulls.. I would try and rebuild the fuel pump, maybe its not pushing fuel fast enough or the vaccum that moves the diapram in the fuel pump is not good from the motor. Could check lines or change lines and make sure they are clamped tight..
Click to expand...
I rebuilt this vmax sx pump with a dennis kirk rebuild kit. A lot of if not all the fuel lines look to be original but they all seem nice and pliable yet. I had started the sled last Friday afternoon to see if the petcock I added would help but no luck. I put just a few drops of fuel down each cylinder and it fired up instantly. I added a new set of handlebars over the weekend and I wanted to make sure the heated grips were going to work so I went to start it late Sunday evening thinking it would take a bunch of pulls but it popped on the first and started on the second. It should start like that after only two days in a warm summer garage but I was very surprised it did.
 
First thing that came to mind for me, was the vacuum line that powers the fuel pump.
The one that goes from the fuel pump, to the case, inbetween 2 of the carbs. I would remove it and check carefully.
Also, may want to make sure your choke cable is adjusted correctly, so they open fully.
 
MURDER YAMAHA said:
First thing that came to mind for me, was the vacuum line that powers the fuel pump.
The one that goes from the fuel pump, to the case, inbetween 2 of the carbs. I would remove it and check carefully.
Also, may want to make sure your choke cable is adjusted correctly, so they open fully.
Click to expand...
I was also thinking the choke might be part of the issue. That was my next step.
 
Does it smoke a lot upon start up. Sometimes that check valve in the oil line leaks oil into the fuel pump while sitting for days.
 
MURDER YAMAHA said:
First thing that came to mind for me, was the vacuum line that powers the fuel pump.
The one that goes from the fuel pump, to the case, inbetween 2 of the carbs. I would remove it and check carefully.
Also, may want to make sure your choke cable is adjusted correctly, so they open fully.
Click to expand...
I'll have to check that vacuum line. The way i have the choke cable adjusted is with the lever flipped all the way on the second position or full choke the cable has zero slack down at the carburetor. I do know I could move the plungers a little more by hand though. I just thought you probable wouldn't want to adjust it tighter or it won't complete shut the choke off.
 
74Nitro said:
Does it smoke a lot upon start up. Sometimes that check valve in the oil line leaks oil into the fuel pump while sitting for days.
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I would say it's pretty normal as far as smoke goes. It's there but nothing excessive.
 
I checked all my fuel lines along with my vacuum pulse line and they are all in great shape. I pulled the carbs off to look at that stuff and decided I could try opening my fuel screws to 1 3/4 turns if that would help? The bowls were full of fuel when I took them off so that doesn't seam to be the issue?? Otherwise I'm tempted to just add a primer.
 
74Nitro said:
Stock reeds?
Make sure they are fully seated/closed.
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Yes just installed new oem Yamaha reeds towards the end of last season. I flipped them back and forth until they sat best they could. I've been trying about everything to help starting.
 
MrSled said:
Make sure the choke circuit is clean. I know you cleaned cabs but you never know.
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I have pulled the bowls and jets and sprayed through the passages of the carbs with carb/choke cleaner after I ran the rack through my parts washer. I didn't pull the choke assemblies apart however. I was afraid I wouldn't get it back together properly. If it's what's truly needed and what I did may have missed it I can though.

EDIT: I pulled the choke assembly and plungers out tonight but they seemed quite clean. I sprayed carb cleaner through them ass long as I had them apart but everything went through just fine.
 
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The choke jets press into the bottom of the carb and extend into the float bowl of course. Use torch tip cleaners to make sure they are not blocked or partially blocked.
Very fine increment small drill bits can be bought at most automotive stores. You could slightly increase the size of that fixed jet also.
 
74Nitro said:
The choke jets press into the bottom of the carb and extend into the float bowl of course. Use torch tip cleaners to make sure they are not blocked or partially blocked.
Very fine increment small drill bits can be bought at most automotive stores. You could slightly increase the size of that fixed jet also.
Click to expand...
I got carb and choke spray to shoot through the choke jets and followed that with a little compressed air. I do have torch tip cleaners but I didn't run those through, just did that on the jets. I'll do that next time I have the carbs out or drill them out a little like you mentioned. Any idea on what size would be a good start?
 
Well heres what I'm at but still taking way too many pulls to fire.

130 psi compression on all cylinders
Carbs are completely clean with 45 pilots and fuel screws at 1 3/4 turns out.
Floats are set right at factory spec roughly 14.3 mm
Choke cable is adjusted maxed on full choke lever
Excellent spark on all three cylinders
Fresh rebuilt vmax sx fuel pump and good fuel lines with a fuel shut off valve
New yamaha oem reeds that all seal good and no daylight visible through them

I had the sled running this last Friday afternoon and shut the fuel valve off afterwards. It sat over the weekend and Sunday afternoon I gave it a try to see if anything I did helped. I got it to start after about 15 pulls after sitting for roughly 2 days.
 
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