Hard starting viper

L

Luke600r

Member
Joined
Dec 9, 2012
Messages
208
Location
Wisconson
Baught my buddy's viper for a back up sled cheap he baught a new sled. We rebuilt the motor last year maybe 600 miles on piston and rings 1 culinder was replated and other to were honed. This thing ran flawless last year and would start no matter what the temp was in 5 or less pulls. Cylinders are ported. Mega power heads. And bender pipes. (He said). The carbs were cleaned b4 I got it Have not pulled them back off yet but this is what's going on. Thing takes 20+ pulls sometimes to start. Once it start it will start 1-2 pulls after that. Leave it sit for 1-2 hours. Same thing pull pull pull. After started will start right back up. And runs flawless. Plenty of power. No bog. No idle problem. Doesn't seen like any jets are plugged. Stator?? Fuel pump ?? Or should I start by pulling carbs back off. Compression is 125 across all 3. And has 3 new plugs
 
Last edited:
You can Pull fuel lines from carbs and turn over engine to check fuel is pumping (messy). I would check you probably have "rusty mag-itis". Open mag side and clean all the rust out. If run on last years gas could be shit gas. double check your carbs are clean and while your at it check your jetting specs...the jets are engraved with a number and you can verify in the tech section there's also a good carb cleaning 101 by mrviper if you've never done it... Could be a spark issue with plug wires or cdi but sounds like once it goes it runs good. Also I've found yammi triples like a bit of throttle when starting them I sometimes have to give mine a bit of thumb. Check under motor for wire rub throughs. That should keep you busy for a while hah.
 
Check your reeds, my Viper was a pain to start for years and I always had to give it a little throttle too. I checked the reed pedals and found them to be chipped and even one was broken completely off. After I replaced them it fires right up warm or cold with no throttle.
 
leaky needle and seats do that... is it rich??? or better yet go out and try to start it pull it for a few times, then pull the spark plugs are they all wet in 1 or more cylinders?
 
Ok had a small amount of time to mess with the viper today. Pulled over 6-8 times to check plugs for wetness pulled plugs. Didn't notice any wetter then the other. Pulled carbs off and gas came out off all 3 fuel lines. And carb bowls were all full with gas. (Seams like fuel pump working ) pulled bowls off and pulled jets. All seamed clean. Flipped carbs upside down and lightly blew threw the lines to try and check needle and seat couldn't blow threw I know not the right way to test but it seams they are ok. Here are the current specs of the sled
157.5 mains
47.5 piliots
3.5 needles
2 turns fuel/air screw
NOT vented to airbox
Airbox mod
Bender pipes
Ported cylinders
Mega power heads at 0062 squash
 
Did you check the reeds? V force are especially bad for chipping.
 
Didn't have time to check reeds. I know they are stock. Cause we had them out last year. But I had to leave for work and didn't get a chance to pull them yet.
 
So I got home from work and started messing with carbs. Knowing my buddy and he lack in doing a job right lol. I decided to pull the carbs complete apart clean and reassemble. Well tearing down after I pulled the fuel/air screw complete out I noticed that two out of three were missing the little o-ring and washer for the fuel screw. U guys think these could be the culprit
 
check to see if the o-ring and washer aren't stuck inside yet.Sometimes they come out all complete,sometimes not.Check your choke set up to see if all 3 plungers are opening exactly the same time and if they open all the way also.
 
Yup checked for o-ring and washer. Like 5 times. Couldn't believe they wernt in there. Mag and pto had neither washer or o-ring. And center had only the o-ring. And yes that is something else I knoticed well taking carbs off was that the choke was not correctly set up. There was slack in the cable. I'm just hoping that these 2 things take care of the problem
 
Luke600r said:
Yup checked for o-ring and washer. Like 5 times. Couldn't believe they wernt in there. Mag and pto had neither washer or o-ring. And center had only the o-ring. And yes that is something else I knoticed well taking carbs off was that the choke was not correctly set up. There was slack in the cable. I'm just hoping that these 2 things take care of the problem
Click to expand...

There should be enough slack to ensure the plungers are closing but too much and they won't open completely. IOW - too much slack means you're not reaching full choke which could cause a cold hard start.
 
Luke600r said:
Knowing my buddy and he lack in doing a job right lol.
Click to expand...

I actually did LOL. Most politically correct way of saying my buddy is a hack I have ever seen.....Glad I am not the only one to have buddies like this! 100% X2 on choke slack being a big factor in cold start up.....much like trying to start it in warming position. Noticed carbs NOT vented to box, I know with stock set up this causes pig rich condition, with your mods I am unsure of effect.
 
Well. It's back to normal. Not sure which it was or a combo. But I replaced o-ring and washers in fuel screws. Re adjusted choke. And cleaned up magnets on flywheel and she starts 2-3 pulls every time. One less thing to done and don't have to worry about I guess. Lol. Thanks guys
 
You must log in or register to reply here.


Back
Top