Crusader engine trouble

M

MarkMuck

Member
Joined
Jan 1, 2000
RO Number
362
Messages
264
1992 454's. 1000 hours.

This started developing last summer. Port engine is rough at idle. Get it up to 1200 rpm and up and it's fine. Starboard engine is fine. Both use the same fuel tank We rebuilt the Holley carb but it still does it. OiL on the stick looks good oil pressure and temp is good.

Any ideas. Tune up?
 
I don't know when/if they changed to electronic, but if your distributors are not, check the spark advance.
 
Actually, if you have points, scrape the rotor and contacts in the dist cap. If that don't do it, do the low speed air screw adjustment...the two little screws on each side of the float bowl.

Let us know if there was any change.
 
You could swap carbs to rule that out.
I'd try an inductive pickup timing light attached to each successive spark plug cable to see if they are all firing reliably at low RPM. That would not necessarily indicate combustion. While doing that I'd check base timing.
I'd also consider a vac gauge test since that can be very revealing in a lot of cases.
Does the port engine reach the same WOT RPM underway as the stbd?
Age of plugs?, and have you inspected/cleaned or replaced/gapped them recently??
 
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