TOPIC: 1969 Mercury 500 thunderbolt gaskets,etc

Getting my old 50 hp motor working again for a trip this weekend and was wondering if Napa or anyone would have any kits for the carbs, fuel pump, etc. Last time I took it out it was running rough and I had to keep priming it to keep it going so I'm guessing the pump needs to be rebuilt again. The carbs also need to be cleaned up and a new set of gaskets. Trying to resolve a still mercontrol unit as well. I have a manual somewhere, but I was wondering also if there is any maintenance/adjusting to be done on the thunderbolt ignition.

NAPA lists a fuel pump repair kit, P/N SME 187804, which is NAPA's version of Sierra 18-7804, which replaces Mercury P/N 23014A 1.

For disassembly/cleaning of carbs, usually you'll only need the Carb Packing Kit, Merc P/N 2015, Sierra 18-70061, NAPA SME 70061.

You might also consider replacing the carb floats with new ethanol-resistant ones:

Merc P/N 110A 1, Sierra 18-7208, NAPA SME 187208.

Maintenance-wise on the ign, you can renew spark plugs (Permagap Champion L78V or equivalent).

Not a lot to do on the distributor, you could pull the cap and check/clean it, but I don't think you can get at it without removing the distributor assy. If you have a good strong spark, and no indicators of problems otherwise, you might consider deferring that maint. to a later date.

You should check/adjust maximum spark advance per your manual, that is an important setting, along with the Primary Pickup. It'll run better with the carb & ign advance synchronized.

HTH & G'luck with your project, have fun on the water!....ed

Thanks! I found my repair and parts manual for it today and think I definitely need to put a timing light on it and sync it. I've never put one on it and ive never got it to idle up like its supposed to. I'm also wondering if the mercontrol linkage on the engine is adjusted right... It's not covered in the manual and you have to push the lever all the way down to get it to pick up speed. on another note, I noticed oil/fuel residue all over the outside of the carbs and looks like it ran down all in the housing. Any ideas there?

Well, the local marine dealer happened to have the carb gaskets and fuel pump kit and they were cheap enough. Fuel pump "looked" ok but I replaced everything anyway. The upper carb was dry but the lower one was oily. I noticed the hose that runs vertically on the block nearest the starter (main bearing balance tube or the cylinder bleed hose). From the parts manual it's hard to tell, but that hose was cracked bad so I assume that's the source of the oily residue on everything. Both look pretty bad and the lower plastic barb broke off one of them also. I'm not a two stroke guy so I'm not familiar with how these function. I see there I supposed to be a check valve in the upper bleed hose connector but mine are all nylon barbs... Is this a problem to use it like that without the check valve?