Srx 700 running rich pto cyl.148.3 jet

M

madpat

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Nov 6, 2008
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32
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58
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Laona, Wisconsin
I have a 98 srx 700.motor with reed spacers,v-force 1 reeds,fresh motor,adjusted power valves,new fuel 93 octane.at idle to 1/3 1/2 throttle plugs look good.when you open full throttle it won,t rev past 7000.pto side plug is wet,middle good,mag good.jets are stock.148.3 pto,146.3 middle,146.3 mag.i dropped the needle(moved clip to the top)on the pto carb same results.I,m going to try a 147.5 pto side(lean it out),and i,m going to swap the coils around to see if problem moves(bad coil).any ideas?I would think it would use more fuel with the reeds & spacers not less? HELP Thanks MadPat
 
Hey why are you having this problem now? What have you done recently? since it last ran good? It is probably something simple.
 
I don't iot is jetting. if the morot was jst freshened are you sure the timing is right is the magneto was off? Even if you were 3 jet sizes off it should rev to 8000.
 
chris189 said:
I don't iot is jetting. if the morot was jst freshened are you sure the timing is right is the magneto was off? Even if you were 3 jet sizes off it should rev to 8000.
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Mag was off.sled ran like junk when i got it.Broke a rod(middle cyl. bottom bearing failed).I went thru the carbs 4 times after putting in a new motor(runs the same as before motor was replaced,but that motor was also rebuilt(could have had a timing issue with that one also?How do you check the timing?
 
That main jet is not your issue. You either have an issue with the PTO carburetor, you may have broken a reed, or you have a coil/cap issue. How does it run off idle and in the midrange? I would tend to think that you pitched a reed, however, I would measure the coils and plug caps first. That is the easiest thing to diagnose, without pulling anything apart. If it's not that, pull the reedblock out, and inspect it. If it is not the reed, move on to the carburetor.
 
You can check the phasing of the crank if you have a degree wheel. You simply put the wheel on the PTO stub of the motor, and measure when each piston is at TDC (you can use a caliper down through the spark plug hole for this). They will be 120 degrees apart from one another.
 
valin said:
That main jet is not your issue. You either have an issue with the PTO carburetor, you may have broken a reed, or you have a coil/cap issue. How does it run off idle and in the midrange? I would tend to think that you pitched a reed, however, I would measure the coils and plug caps first. That is the easiest thing to diagnose, without pulling anything apart. If it's not that, pull the reedblock out, and inspect it. If it is not the reed, move on to the carburetor.
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Idle and midrange are good when you open it up it falls on it,s face won,t rev past 7000,pto plug looks wet.By the way i,m using the same stator as the 1st motor.
 
chris189 said:
Hey why are you having this problem now? What have you done recently? since it last ran good? It is probably something simple.
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Never ran good bought it cheap knowing something was wrong.
 
'98 and '99 srxs had the mag cylinder jetted fatter than the '00-'02 srxs, which had the pto side fatter. switch your pto and mag cylinder main jets around and try that. also, check coil and spark plug caps like others suggested.
 
Well, do what i suggested. Start with the coils, then check your reeds, then move onto the carb. How does it sound at WOT? Burbly?
 
just cross the spark plug wire from the cylinder that seem flood and the one that work ..98-99 don't care where u put spark plug wired
 
valin said:
Well, do what i suggested. Start with the coils, then check your reeds, then move onto the carb. How does it sound at WOT? Burbly?
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x2 if it doesnt work better with criss cross wired than look at reeds and carb again. .float height ,hey valin have u ever see that screen under the needle and seat ??? i never notice it but it seem it block
 
modsrx said:
x2 if it doesnt work better with criss cross wired than look at reeds and carb again. .float height ,hey valin have u ever see that screen under the needle and seat ??? i never notice it but it seem it block
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I checked the screen when i had carbs off,it,s clean(i removed and cleaned when carbs where off.I,ll try the coil/wire swap if that don,t do it i,ll swap the jets around.Why would one year have bigger jets on pto side and on mag side the next year?
 
Hey i have an idea, you did some crank work. Maybe the crank has some serious runout. Maybe it was dropped before installing? If it has runout you could have enough vibration to restrict the motor from turning freely at high rpm. Just a though, probably not what you want to hear. I have found srx's to be very reliable with ignition and stuff. just an idea.
Also, you think it's jetting? check your choke plungers in the carbs. They dump the fuel in if they are not seated all the way.
 
Valin I think you hit it on the head.. Check Compresson, plug, cap, coil, then move to carb and reed.. Simple swaps will issolate the problem.. Do you have a laser temp meter?? They work really well to help issolate a problem like this..
 
did u put back the little round plastic over the main jet ??make sure u didnt put backward
 
I did put the plastic back & i double checked it cause i was ? that also.I do have a laser tester.The pto side pipe is very cool compared to the others.it runs great on all 3 at idle to 1/3 throttle.at idle all 3 pipes are hot.The only other thing i,m thinking is it,s leaking coolant into that cylinder when the cyl. pressure goes up(thats what it seem like) but the plug is wet with gas not coolant(i had a 800 storm 3 cyl.that had a bad head that did that but you could see water droplets on the plug.
 
so the pto pipe is cool went ???make sure all 3 carb open at same time ....do a spark wire swap and run it again take haft of a second to do it ...make sure no one play with the needle position
 
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