old mercury problems

I have an old 30 hp mercury that has always served my family well. It ran without a problem for years but has not run in 3 years now. I took it to a local mechanic and he had her back running in no time at all and said it was in good shape. He cleaned the carb and it started right up he said. Said there was a small gas leak around some filter I believe but said that stopped after it cranked and didn't give it a second thought.

I took it out the next weekend and she cranked right up for me and we fished fine. I took her back out last weekend and she would not crank at all. It tries to turn over but never does. It sounds like it is not getting enough gas.

Is there something I can do to work on this motor myself or am I better off taking it back to the shop?

Thanks

T

I would get a spark tester and check for spark ($9 at autozone). If it won't cross a 1/4" air gap with hot blue spark, you have ignition problems.
If squirting a little fuel/oil mix in the carb throat allows it to run for a few seconds, then you have a fuel problem. Either the float needle is stuck, or you have a stopped up carb. If the mechanic didn't replace the 30 year old fuel lines, then there's a good chance that is your problem----ethanol deteriorated fuel lines putting particles in your fuel system. To have a reliable engine these days, you need brand new alcohol resistant fuel lines, clean and fresh fuel in a good tank with a new fuel line and primer, and a spotlessly clean carburetor. I would also check your lower unit oil for water intrusion.
JBJ

If the motor won't "turn over", remove the spark plugs, and try to turn the motor over with a ratchet and socket. if it still won't turn over , two things to check and they are both bad, first take an led pin light and look into the spark plug hole, see any dents , chunks of aluminum? if so then something in that cylinder may have broken, ring or piston and it will not let the motor turn over because it is hitting the top of the block, nothing there drop the lower unit to make sure that water hasn't rusted and seized the top drive shaft bearing causing the lower unit to not allow the motor to turn over, the drive shaft goes into the crank and if it locks up, starter will not turn over the power head. I would guess lower unit, did the oil get checked, changed prior to running, if there was no oil the bearings will weld them selves to the surface they are touching, I have seen this in motors that sat and then tried to get running, maybe was the lower unit drained and not refilled?

If the motor is cranking but won't fire then like Bayoumonster says check spark then if nothing else a very small shot of gas down the carb to see if it will fire , no spark, stator or switch box, no gas , fuel pump diaphram, fuel lines , primer buld and or carb has a stuck needle

Tries to turn over.,..

Check your battery cables

Thanks for the help guys. I am planning on check out the things yall mention this afternoon. I do know that it ran fine just a few weeks ago and the lower unit oil did get checked and it was fine. My gut feeling is that this is something small but I am not sure what it is so that is why I came here. I will update yall tomorrow

T

my Mariner did the exact thing you're describing. I had it running not long back, then when I took it out recently it wouldn't start. turned out the inlet needles in the carbs were stuck so no fuel getting to carbs. rebuilt them, it runs like a banshee now. it doesn't sound like the mechanic rebuilt the carb, only cleaned it.

how old is this motor?

well after doing what yall said it looked like I had ignition problems. I took it in to the shop and I need a new cd box and interferer. Hope to have her out of the shop next week.

Thanks for the help

T

when you say turn over do you mean the starter wont turn the engine over or is the engine cranking on just wont run?