1972 Mercury Thunderbolt 800 whats next??

[Gomer50]

Okay need just alittle more advice,after rebuilding carbs,fuel pump.replaced bulb,fuel lines.Starts pretty good, Idles pretty good.Hole shot is great but now comes the kicker.At 4200 rpm it runs decent,at WOT throttle it spits and sputters, gerking and wants to go just cant do it.I had put new spark plugs in it from NGK.And these did not work at all so put back the old autolite plugs.I am wondering if these plugs are fouling at higher RPM.Thanks guy's I read here alot and am very thankfull.Everytime I take it to the lake in the hopes that I have finally got it right BUT NO.Thank the Lord I got patience.

 

[Chris1956]

Re: 1972 Mercury Thunderbolt 800 whats next??

Sounds fuel related. Have someone pump the fuel line primer builb at high speed. If it gets better, look for air leaks in fuel system.