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Roy Belding
Roy Belding, RV Mechanic
Category: RV
Satisfied Customers: 4656
Experience:  10 years expierence on all makes and models
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Good Morning, I have a 1984 motorhome with a Ford 460 in it

Customer Question

Good Morning, I have a 1984 motorhome with a Ford 460 in it and about 54000 miles. I believe it's a 4 barrel holly or eldelbrock carb. It runs like a champ, I just drove it from Denver,CO to Portland, OR. It passed Denver emissions, but just failed in
Oregon because it was 714/350 on hydrocarbons, everything else passed with flying colors. The DEQ tells me it's unburnt fuel, all the things they suggest on the paper have been done recently enough, like plugs, wires, distributor, etc. I got this motorhome
from my folks who used it exclusively in Colorado mountains so it's probably tuned for that, would bringing it down here to Portland, OR make sense? And would a carb adjustment do it? And how would I adjust the carb if that's the case. Thanks Wil
Submitted: 1 year ago.
Category: RV
Expert:  Roy Belding replied 1 year ago.
good morning my name is ***** ***** I will assist the emission standards are different from state to state. it may have passed in Denver because of the age and specs. to get the specs down is not just an adjustment. It is a matter of timing, carbon build up inside the engine itself, air pump operation on the motor, jet sizes in the carb, and the ability of the cat converters to process the un burned fuel. Roy
Customer: replied 1 year ago.
Hi Roy, thanks for the help. Oregon is actually the less restrictive state on 1984's. In Colorado the HC limit is 300, in Oregon it's 350. I also know it's CAT exempt in both states being a motorhome. It's only HC's that I'm having a problem with, all other tests are well below the allowed limits.How do I deal with carbon build up? Is that an typically an issue at 53000 miles? A mechanic in Denver went fully through the motor last year and it's only been driven this one trip since. Like I said it runs like a champ, no hesitation, doesn't stall, even idles smooth, could it still do all this with a timing issue? It's worth noting it just drove 1200 miles at 65 mph. It was getting about 220 miles to a tank of gas which is better than the 200 my dad has always experienced climbing up and down the rockies.Caps, rotors, dist, plugs, wires, vacuum hoses, belts, have all been done with in the last 10K miles. So I guess that leaves me with:1) How do I deal with a carbon buildup?
2) What jets should it have?
3) How do I check the air pump?Thanks
Expert:  Roy Belding replied 1 year ago.
ok, the carbon is cleaned with products such as GM top engine cleaner. a shop can do this and it cleans the intake, valves, pistons of all carbon build up. great product. the carb will have to be removed and the jets removed and the size is stamped on the jet itself. the air pump is external and works while the engine is running. it injects air into the exhaust to help burn the unburnt fuel that leaves the cylinders before heading to the exhaust pipe. a shop can monitor this system to confirm it is functioning correctly. you would ned a scan tool to do it yourself. Roy
Expert:  Roy Belding replied 1 year ago.
how are you making out please dont forget to rate me as it is the only way we get paid for our efforts.