Ford Engine backfiring above 2000 RPM

[dmurray62]

I have a 1972 Ford 302 2 barrel I/O with Mercruiser 888. It runs great in Neutral and in gear on ears but when it gets in water (under load) it backfires above 2000 RPM. Boat and motor are in good condition but sat in storage for 14 months before I bought it. Treated old fuel and added new but too much to dump. Sprayed Creep in carb and changed all fuel filters. Fuel looks fine. Dist has cetrifical vacuum and points look fine. Is this timing or should I rebuild carb? Thanks for ideas.

 

[Haut Medoc]

Re: Ford Engine backfiring above 2000 RPM

Welcome to iboats. .Well, I would check the timing first,because that's free. 10* btdc, could be lots of things, but check that first.J

 

[Wellcraft 89]

Re: Ford Engine backfiring above 2000 RPM

Did you do a compression test on this motor ?<br />looking for burnt valves or stuck open valves?<br />How about a sparkplug wire in the wrong place,or the distributor in one tooth off if you removed it.<br />When you say it runs fine on muffs no missing or shaking? <br />could be water in fuel <br />Rich

 

[dmurray62]

Re: Ford Engine backfiring above 2000 RPM

Thanks for both replys. I did chnage the fuel-water sep and 7 days later dumped contents into a jar and saw no separation, just gasoline. I may still have a fuel problem but I don't suspect any stuck vales or compression issues. The boat ran well until winterized in Fall '03. It really runs well in neutral, at low or high RPMs, no missing at all. I'm thinking dist as you mentioned.

 

[Haut Medoc]

Re: Ford Engine backfiring above 2000 RPM

I would thnk fuel pump, it should deliver 3-6 psi. Does your sight glass(bowl) show anything ?

 

[llerrad]

Re: Ford Engine backfiring above 2000 RPM

Have same engine and year. check dwell, timming. change dis. cap/rotor and condensor. Every time I have had this problem it has been electrical like dist. cap or bad coil wire, besides it's the cheap stuff to hit first. Plugs too.

 

[dmurray62]

Re: Ford Engine backfiring above 2000 RPM

Glass bowl is dry, thank goodness. Now rebuilding carb and changing plugs, wires, points and the works and will check timing. Compression was fine, no stuck or burnt valves. I hope this will solve problem. Carb was gummed up a little on visual. Thanks for everyone's time. I will report latest results.

 

[dmurray62]

Re: Ford Engine backfiring above 2000 RPM

Rebuilt carb and changed points, condenser, plugs and plug wires. THEN discovered plug wires were in wrong firing order. May have been the problem all along but can't say for certain. Also adjusted timing. Running great now!

 

[Haut Medoc]

Re: Ford Engine backfiring above 2000 RPM

Good deal, it never hurts to do that stuff anyway. Those Fords,( I have one), can sure get ya confuzzled if you don't pay attention. Especially if you're used to working on Chebbys!.....JK