Jet Sizes For 1987 70HP

[spucky]

Hi, can anyone tell me standard sea level jet sizes for this 1987 ( no tag on engine ) 56 CU inch 70. Carb tags are "431705 MX 30 I L". Carbs have clearly been mauled over by someone, have 65 mains and 29 idle bleeds in them now. Manual I have list jets as a chart, but no specific size. The engine idles ok, noses over on throttle up, 125 PSI in all three. Thanks.

 

[OBJ]

Re: Jet Sizes For 1987 70HP

The number you posted (431705) is the original carb part number.<br /><br />The parts break down lists the main jet as 64 and the idle air jet as 33.<br /><br />It is possible someone has tweaked the jets for better performance.

 

[Dhadley]

Re: Jet Sizes For 1987 70HP

Make sure the main jet is a D jet, not a C jet.<br /><br />Looks like someone was trying to richen up the jetting.