Blue Smoke - choking

[marty]

Have a 20 Year Old Ford 4600 SU and last year it began choking out and then discharging blue exhaust under higher RPM and under load. The dealer replaced the fuel pump and it seamed to help a little.

The condition seems to be getting a little worse, so when I was replacing the fuel filter I noticed the injectors had never been changed. I replaced the injectors and the it still smokes badly.

Could this be bad valves or seats? Could a person replace the valves and seats from the top - under the valve cover? Other sugestion??

Thanks in advance!!

[Anonymous Poster]

Marty

I'M no expert but to me it sounds like very worn oil rings or even broken rings.

[woodmills1]

yes, blue smoke usually means oil, so rings worn, broken or cracked. maybe vale seals but smoke due to seals usually clears up after intial puffs on starting. Do a compression check to find the offending cylinder.

[Egon]

Does the crankcase oil level go down between oil changes?

Egon

[marty]

I checked the tempature on each cylinder and they seam to be the same. The tractor does not use oil either and the breather seam to be fine. I did notice that it only starts to choke out at low ideal and at high RPM's.

There is no unusual smoke during moderate RPM's. I have to believe it is fuel related and the injector pump seems to be a high suspect.

[normde2001]

Check for a plugged up muffler.

[bgott]

Make sure your thermostat is working and your engine is warming up. I threw a load to my tractor a little too early today and it started cutting out and blowing blue smoke just as you described. I let it warm up a little longer and the problem went away.

[RickB]

See the post above concerning old fuel and fuel conditioners. Engine operating temp is critical, they weren't designed to putz around with the coolant temp below 180.