Vapor lock

Message

kstevens · #1 Post by **kstevens** » Mon Nov 05, 2012 2:27 pm

The quad runs great for about a 30 min ride, then quad starts to spit and sputter like its running out of fuel, if u hold it at 1/4 throttle or so once it starts to act up it runs smooth, hammer the throttle and it will bog as if its not getting fuel, very similar to a vapor lock on a carb application, and it will eventually shut off, after about 5-10 of sitting with fan running it will eventually fire up and run again for about 10-15 min no problem, then the process starts all over again. I have a fairly new fuel pump (within 2 yrs old) I have replaced, plug, coil, temp sensor, fuel filter. I thought about fuel pump relay but figures they either work or they don't.... PLEASE HELP, this is aggravating
Thanks in advance

Blasterboy11 · #2 Post by **Blasterboy11** » Mon Nov 05, 2012 5:17 pm

Silly to ask, but check the connector to the pump my moto did the same thing a while ago, same symptoms and it ended up being the clip cracked and slipped loose.

kstevens · #3 Post by **kstevens** » Mon Nov 05, 2012 5:32 pm

QUOTE (Blasterboy11 @ Nov 5 2012, 12:17 PM) <{POST_SNAPBACK}>

Silly to ask, but check the connector to the pump my moto did the same thing a while ago, same symptoms and it ended up being the clip cracked and slipped loose.

All wires and clips are tight, fuel quick disconnects have been gutted

speedracer · #4 Post by **speedracer** » Tue Nov 06, 2012 1:43 am

I have read about fuel boil on cdales,wouldnt the symptoms be similar?Maybe try some heattape where the header is near the tank,maybe even wrap your header.Is your gas cap venting?

kstevens · #5 Post by **kstevens** » Tue Nov 06, 2012 2:02 am

QUOTE (speedracer @ Nov 5 2012, 08:43 PM) <{POST_SNAPBACK}>

I have read about fuel boil on cdales,wouldnt the symptoms be similar?Maybe try some heattape where the header is near the tank,maybe even wrap your header.Is your gas cap venting?

This is a relatively new issue, it just started to do this one day and has continued since

cannondale27 · #6 Post by **cannondale27** » Tue Nov 06, 2012 4:22 am

You are wrong about the relay.When they act up they do so exactly as you are describing.Try removing it.

kstevens · #7 Post by **kstevens** » Tue Nov 06, 2012 2:40 pm

QUOTE (kstevens @ Nov 5 2012, 09:02 PM) <{POST_SNAPBACK}>

This is a relatively new issue, it just started to do this one day and has continued since

Thanks, I will try that this weekend, it is the relay under air filter, correct?

cannondale27 · #8 Post by **cannondale27** » Wed Nov 07, 2012 2:11 am

Yes thats the one.Just take it out and see if it runs right.

kstevens · #9 Post by **kstevens** » Wed Nov 07, 2012 11:42 am

If it doesn't need pump relay to run, what's the purpose of having one?

wistech · #10 Post by **wistech** » Wed Nov 07, 2012 4:51 pm

They run fine without them. If you really have vapor lock in my experience there will be no fuel flow in the filter and your tank will be a rolling boil. It only happened to me after several hours of slow riding in extreme heat so a half hour is doubtfull. More common than not is an air leak in your suction line. Most likely the quick connect oring.