Mercruiser 470 backfires out of Carb

Question

My 1983 Mercruiser 470 started to break up while on cruising rpm. Now she is not getting full RPM, I'm getting 3500 and then for short spurts, she goes up over 4000, but back to 3500 to 3800 RPMs. On the starts out of the hole, she pops out of the carb and sometimes stalls out. Also, I have found that when I punch it from idle, there is a hesitation before the engine responds with either the lean pop or acceleration. I have changed the point and condenser, changed the fuel filter and even add a Racor 10 micro Fuel Filer / Water Separator...but I still have this issue.

Does anyone have any idea's?

Thanks

Answer 1

+1 on the timing, also check for a vacuum leak

Answer 2

You need the timing and carburettor checked.

Answer 3

definitely timing, worth checking the vacuum, also if you have a vacuum advance, be sure hoses are all connected to that, also, if there is a vacuum advance, the dashpot could be defective

Answer 4

If you have a Quadrojet check the filter in the carb where the fuel line goes in> Check timing>