Will not start - I believe it's a carb/fuel delivery problem
Posted: Thu Mar 29, 2012 1:48 am
Hello fellow XJ riders. New here, but have been lurking for the last two weeks reading all the great tutorials on carbs.
Bike history
It's a '94 Yamaha Seca II, sat idle for about 3 years. The carbs and tank were not drained, but fuel stabilizer might have been added to the gas in the tank.
After replacing the dead battery the bike would crank, but would not start.
What I have done to it since
Carbs
Bike history
It's a '94 Yamaha Seca II, sat idle for about 3 years. The carbs and tank were not drained, but fuel stabilizer might have been added to the gas in the tank.
After replacing the dead battery the bike would crank, but would not start.
What I have done to it since
Carbs
- Took off the carbs, took them apart and soaked all brass pieces in brake cleaner - main jet, pilot jet, PMS, air valve, and emulsion tubes.
- Last piece of the main jet and the enrichment tube I couldn't take off, so I sprayed them with carb cleaner and blew them out with compressed air.
- I did not use a metal strand to clean out the enrichment jets, so they might not be completely clean. Everything else should be surgically clean - I have taken the carbs apart three times and I have gone over everything very carefully.
- I did not replace the main jet and pilot jet o-rings and I did notice that one of the main jet o-rings was not in good condition, but I don't believe that it could cause the bike to not start at all, but rather to run poorly at the most. Once I receive the new o-rings in the mail they will be replaced.
- replaced the spark plugs just in case. Ran a compression test and all cylinders tested between 150 and 160 PSI.
- if I spray some carb cleaner into each of the carbs the bike will start for a half a second (rev up to 4k, or higher if more carb cleaner is sprayed) and then die.
- took apart the fuel petcock and everything looked good. Fuel is flowing when set on prime.
- replaced the inline fuel filter just in case
- Tested the fuel pump by putting the output hose into a cup and cranking the engine - the fuel is flowing but it seemed to be a very weak stream. How fast is the fuel supposed to flow out of the fuel pump?
- The tank was a bit rusty so while I had the carbs out, I filled it up with a gallon of de-ruster. After I was done, I made sure to drain the tank and to run water through it as well as let it dry after before mounting it. Unfortunately, the two tubes ('on' and 'res') in the petcock, that also act as filters, are missing so the pump is picking up from the bottom of the tank. To add to this, I also made a potentially critical mistake - while jerry-rigging the tank to work off to the side of the bike, so I had easy access to the carbs, I removed the inline filter between the petcock and fuel pump and fitted a straight hose. (I needed it to be longer and didn't bother installing the fuel filter) Not sure if this might have cause the fuel pump to clog up... Again, need to know how much fuel a correctly functioning fuel pump is supposed to put out. I have since put in a new fuel filter (I made sure that it is mounted in the correct direction) to make sure that no more gunk gets into the fuel pump or further down the line.