Reply To: 1975 Merc 650 running issues

[shoestringmariner]

mercuryspecialist wrote:

I agree that checking/cleaning the distributor cap is excellent advice. Possibly a new distributor cap carbon brush & spring might be a good idea also. I cannot see the application of WD40 on a upside-down mounted distributor cap to be helpful.

Carburetor float levels and a stretched fuel pump diaphragm would be two other causes.

The timing belt is not adjustable for tension, and ½ inch does seem a little high, so a new belt may be needed. If it is the original timing belt, it is due. The two sealed ball bearings (which support the rotor shaft) should be considered also (if original), or a new belt will typically break when a bearing(s) binds.

Regards,

Joe

(770) 597-5992

Excellent, thanks so much. I doubt it is original as it looks petty good. I’ll change it this winter to be sure. Appreciate the tip on the bearings.
For this week, I think I’ll leave it be and let it dry out in the garage so I doint mess it up and ruin the weekends plans. The plug wires are old. I’m afraid to disturb them too much.