weasel4
Alberta
Senior Member
Joined: 07/06/2003
View Profile
 Offline
|
tonym2180
Yo you don't need to disassemble the carb to check the internal power valve movement. Take a 1/8 cotter pin, straighten it out and put a 1/8" 90 degree bend on one end. Insert the bent end into the vent tube and gently search out a resistance in the carb. The power valve is spring actuated and should be easy to push down. If it is stuck in the down position use the 90 degree bend to lift it up and free it up. The power valve bar, once it is free should respond to light finger pressure to push it down and it should bounce back up freely.
HTH
BTC
|
tonym2180
davie
New Member
Joined: 02/02/2012
View Profile
Offline
|
I will try that this weekend I appreciate all the good advice
|
Mustang7370
Washington State
Full Member
Joined: 12/10/2011
View Profile
Offline
|
Another thing that can happen is the fuel pickup tube in the fuel tank can get pinholes in it from corrosion. This aerates the incoming fuel and can cause momentary losses of fuel pressure. I have checked for this by temporarily installing a clear piece of hose in the fuel line. It should have a solid flow of fuel. no bubbles whatsoever.
Chris and Kelli Withers
Ferndale, WA.
|
PaulJ2
Northwest Oregon
Senior Member
Joined: 12/23/2005
View Profile
Offline
|
tonym2180 wrote:Yes changed the fuel filters twce,I didn't tear into the carb yet so I don't know if the internal metering rods are working the secondaries are though. I went through everything today,timing was dead on and was advancing with the throttle ,checked pcv,vaccination line and air cleaner reflector...all fine. The heat riser is not stuck I could move it open and closed by hand but the vacuum cannister and rod even after a 30 min ride stayed in the same position the rod had pressure pushing it out from the cannister,I think its staying closed. I can disconnect the rod and easily move the flap by hand and there is vacuum going to it. I'm just unsure which position is open or closed.
Did you remove the vacuum advance hose when you checked advance? Vacuum advance moves with throttle normaly, mechanical advance moves with speed only. Can be confusing.
As for the cannister, a spring pushes the rod down (closed) and vacuum pulls the rod up (open). Controlled by a sensor inside the air cleaner. Maintains 100 degree temperature.
|
mr300ce
Mojave Desert, Ca
Full Member
Joined: 10/27/2011
View Profile
Good Sam RV Club Member
Offline
|
I don'tknow what happened to my post from yesterday.
But.....did these problems happen before you started working on it, and that's why your trying to fix it.....?????
Or did these problems start happening after you began working on it ???
If after....then better re-check all the work.
Fulltime livin' & lovin' it in '94 Bounder 32h.
Chevy 454ci Retire in 3yrs.
|
|
|
tonym2180
davie
New Member
Joined: 02/02/2012
View Profile
Offline
|
Yes I checked timing with vacuum advance disconnected...4 degrees btc and 18-22 with throttle,and yes was doing this prior to the work just not as bad,it would stumble for a second then pick right back up.i don't know if temperature has anything to do with it but when It first started acting up it was cold out and these symptoms were scarce,the hotter the temp gets outside the worse the symptoms get. I've double and triple checked all work done, it seems to me the culprit is the heat riser canister has the valve stuck in the closed position,would that cause the falling flat when shifting into high gear getting on the highway....too much backpressure?
|
enblethen
Moses Lake, WA
Senior Member
Joined: 01/05/2005
View Profile
|
Ambient air temperature would not effect the running.
Higher engine RPM and heavier loads will cause excesive back pressure. If the engine cannot breath it will bog down. It would get to the point of running on four cylinders, right back would be almost useless..
Bud
USAF Retired
Suzuki XL7 pushing Pace Arrow
|
Jagtech
Sunny Southern Alberta, Canada
Senior Member
Joined: 06/11/2009
View Profile
Offline
|
Jagtech: "Do you have your vacuum advance connected to manifold vacuum or carb vacuum? Makes a huge difference. "
PM from Rvrepairnut: "you have absolutely no idea what your talking about in this matter
just for kicks explain to me how a engine will have more or less power if the vacuum advance is hooked to ported Vacuum verses full(manifold) Vacuum?"
Jagtech reply: Of course.... manifold vac at full throttle is 0". Carb (ported vac) at full throttle, vac is high (14" approx). Which do you really want to your vacuum advance at full throttle ???? Makes a difference!
BTW, thanks for the vote of confidence about my knowledge
1998 Triple E F53 with 460 Ford
1995 Jeep Wrangler toad
.jpg)
|
tonym2180
davie
New Member
Joined: 02/02/2012
View Profile
Offline
|
Thanks for all your replies I will go through everything suggested on Saturday and post what I find. Tony
|
PaulJ2
Northwest Oregon
Senior Member
Joined: 12/23/2005
View Profile
Offline
|
You want the vacuum advance ported generally. When you open the throttle you want the timing to advance a bit quickly to help eliminate hesitation or bog. Manifold vacuum is high at idle and drops when the throttle is opened, opposite of what you need.
In the old days of pre-emission, rich running engines it made little difference, but today is a different story with leaner running engines.
One more thing--disconnect the egr valve hose if you haven't already (assuming you have egr) take that out of the mix and eliminate one more thing.
|
|
|
