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Old October 13th 17, 04:55 AM posted to rec.autos.tech
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Default Why is my 1985 s 10 2.8 engine so hard to start ?

On Saturday, October 7, 2017 at 6:42:33 PM UTC-5, Scott Dorsey wrote:
> > wrote:
> >Ok,i have been searching for an answer to why my truck is so hard to start.=
> > I have done everything i know to fix this but no luck yet . I have put a r=
> >e-manufactured carburetor on it.I have checked all the vacuum lines,replace=
> >d the fuel pump. manual pump. I have a clear fuel filter that look good. I =
> >have done a tune up,plugs,wires,cap,pickup module,exc... I have even done a=
> > compression test that passes easily. The engine runs good, its just hard t=
> >o start. Im stumped !

>
> Fuel, air, spark, timing, and exhaust.
>
> Is the mixture good? Is the choke closing down for starting and then opening
> up once the engine warms up a bit? Look at the butterfly and mark where it
> sits with a sharpie. If you block it partially with your hand or with masking
> tape, will the engine start properly? The fuel mixture needs to be extra rich
> for starting. The automatic choke sets it that way, if it's working, which
> it often doesn't.
>
> If you put the timing light on it while it's running properly, do the marks
> line up? And then when you put the light on when you're trying to start it,
> is the timing retarded or do the marks still line up? The timing should
> shift severely back for starting and then the vacuum advance move the timing
> up once the engine catches. Make sure it's moving the timing, don't spend
> your time dicking with the vacuum system unless you verify that it isn't.
>
> Is there a good hot spark when you pull a plug out and watch it? An awful
> lot of "carb problems" turn out to be ignition problems.
>
> If you disconnect the exhaust system, will it start right up? A partial
> exhaust blockage may produce high back pressure at starting, but then the
> blockage may be forced out of the way once the engine starts running.
>
> Don't just replace things, check them out one at a time. Think about what
> is different between starting and running... and three big things are the
> choke position, the timing advance position, and the exhaust pressure...
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."


Thanks Scott, i have done all you have suggested. I am somewhat mechanically inclined,i fix all my own issues, but this has me stumped !
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