Starting on PRI

I have an xj550 maxim 81(I think). When I start it, I always have to put in prime and full choke to start otherwise it wont start. Is this correct? If not can you tell me what I can do?

 

Full choke is correct on initial startup. If you need to leave it on PRI to get the fuel going - I would say you have a vacuum problem. Check the hose going from the petcock to the carb boot to ensure it isn't blocked.

You may need to rebuild your petcock.

I'm sure others will chime in.

 

Thank you

Another question. If I shouldn't have to use PRI from starting, when would i use it and what is it's use?

 

PRI is short for PRIME. It is used to prime the carbs, that is fill the float bowls in each carb so that fuel is readily available for the engine.

Prime is more often used after you have drained all the gas out of the carbs for whatever reason - storing for winter, maintenance etc.

 

My bike always needs to have the petcock set to prime for a cold start, if it sits for more than a few days...otherwise it needs to crank for about 10 aditional seconds more to build enough vacuum to get things going.

Turn the petcock to prime, wait a few seconds, and it will fire up with a short stab to the starter button.

I do not have any vacuum/petcock/hose problems: the petcock pees a solid stream when open, and has zero leakage when turned off.

 

Well now - I didn't know that. I'm usually good to start after a couple of days but after a couple of weeks - it can be a bear. I'll try that next time.

I'm not sure if garofski is starting his bike all the time like this or after it sits for a couple of days.

 

After a good ride, go back to your bike after it's been parked for about 15 minutes, and see how warm the carbs are. Unless there's a cold breeze across the beam, the heat rising off the engine will get the carbs very warm, which will evaporate the front end off the fuel that's already in the carbs.

That heat and a little time will lower the fuel levels a bit, but the greater effect is that the components in your gas that help to start a cold engine are the first to depart when things get hot. Stop for a lunch break, and it's no problem...park overnight, and the morning's first startup will either need prime or a little extra cranking. No biggie either way.

This characteristic (needing prime for easy starts) became more noticeable after I put in an engine that produces more heat. :roll:

 

Needed to ask, I have a aftermarket petcock on my XJ & it has 3 settings

1. On
2. Reserve
3. Off

Since i've drained the carb's the bike seemed to have started fouling plugs on one particular cylinder, am not sure if it's related so needed to confirm if by any chance the aftermarket petcock is what's causing this, 2ndly is there any harm in using such a petcock?

Ty!

 

Your petcock choice is fine, no harm; it's just a different answer to the same question. More bikes use that type than the vacuum variety that XJs have.

Which cylinder is fouling plugs?.

 

I only use after a few days. But recently i have been using it to start all the time, however i have had the carb's cleaned and didn't use it this morning. So hopefully will only have to use it when i haven't riden it for a few days/weeks.

Thanks for your help every one

Cheers