TOPIC: Troubleshooting help again please on new problem.

Well my awesome boat is done. Spent lots of time running wires and mounting everything as clean and professional as I have ever done. Very proud of this boat that Mike and Mike Blessed me with.

Got out to test today and my big old Merc tower after 8 years of maintance free operation (pretty good for a motor made in 1970.) Well as you know I had rebuilt one of the carbs and cleaned the other 2 before I sank my old boat and motor was running fine until the boat started to sick. At that time it started missfiring and chugging upon acceleration. My thoughts at the time were water in gas from boat sinking before I knew it.

So I put cleaned dry plastic 14 gallon tempo tank with new fittings and new hoses in new boat. Drained all 3 carbs. Ran new gas with Stabil and Seafoam with my always used Quicksilver 2 stroke oil. Have new marine water seperator and extra see thru glass fuel in line filter after bulb. So I thought all would be good. NOTTTTTTTTTTTTTTT

Motor starts right up and idles smooth and accelerates smooth out of gear. However when put in gear the motor shakes and badly stumbles trying to get past 12mph. You can feel it like it wants to catch and take off but it seems to missfire and will not power up and shakes and grunts. Like and old man like me . Squeeze ball and no change. Ball solid. Its getting gas. When it dies smoke comes out of bottom carb. Like its not running right in gear. Then it would not run much at all. My thoughts are now fouled plugs. These plugs are 5 years old but I clean them. I can start it again and it idles fine. But under power it seems like it will blow up!

Do not have funds to rebuild so if it can not be fixed by me or friends it will have to sit until I can fix it or replace. The Honda 4stroke kicker does me good so I can still fish my close areas. Just kinda bites that I am having issues with this old motor that has treated me right for years. Any old merc guys with some troubleshooting tips for me?
Will check compression tomorrow.
Thanks

Tod

Its a Mercury 1970 model 1250hp 6 cyl tower of power.

I'm no expert but sounds like electrical to me? Water in something that never dried or theres a bad connection not allowing full current flow? (Notice the question marks ) Just the area I would look at. I wouldn't run it like that, might not be a good idea, like to hear what the real sharp Merc guys say

did you ever remove the distributor to get at the carbs? did you align the timing marks and re do the lynch and synch? That may be the culprit.

No I did not touch the distributor or the timing. Someone else mentioned that on another forum as well. However without touching it could this be an issue? I will go inspect cap to make sure it has not cracked or broken.

Thanks all for helping. I am at my wits end? COuld it be the spark plugs?

Could be wires, do simple cheap things first. Spray wd-40 in the distributor cap and wipe clean, leave a film is ok, spray it everywhere, wont hurt. wd displaces moisture. Yep if cap's bad could run ok till powered up but think it would run bad slow also, been too long since I had that problem to remember. Check and clean around coil also. Wonder if the coils weak or shorting from the dunk. If you know how to check for a Hot spark and thats good I'd recheck the carbs, sometimes its hard to tell the difference from electrical and carb problems like yours but still thinking elec.... If you can run it at night you can check for a jumping spark from plug wires. I've seen car plug wires light up like a christmas tree:) Might also use a screw driver with a long wire grounded and run the tip along all the plug wires to see if it jumps but needs to be pretty dark usually. Not such great ideas but better than nothing I'm thinking, well sometimes ps. if new plugs are fouling and there the correct ones, plugs aren't your problem. There fouling most likely from unburnt fuel. Check for hot spark,Check for hot spark,Check for hot spark,!!!! loud snapping...

Thanks I will check. Oh by the way. The motor never was under water at anytime past lower unit.