My mercury outboard motor wont start,,, Why?????

Question

iv taken over the family boat, and its running 85Hp Mercury Thunderbolt, its a great motor im told but i cant get it to run, i read that Daniel C was havin the same probelm with his outboard motor, firslty howdo you know if your spark plugs arnt firing properly , and secondly, what precautions should i be taking with an old motor,

if anyone could help, that would be greatly appretiated

Luis D

Answer 1

First things first...it only takes 3 things to make an old motor like that run; fuel, air and spark. Is the engine getting fuel? If the engine is a bit on the older side of things, remove the carbs and clean them. This may mean some disassembly, but just make sure you put everything back in in the order it came out. Use a good carb cleaner or parts cleaner, but make sure the parts are dry before you put them back together, as the combination of fuel/carb cleaner/compression makes for a bad day. While the carbs are off, pump the fuel line pressure bulb to make sure fuel is coming out of the fuel line into the carbs. Reinstall your carbs, making sure you have a good seal with a gasket or gasket maker to the engine block.

Now you'll want to test for spark. Like the other answer, you can remove the spark plug, place it into the spark plug cap and then place the end of the spark plug on a non-painted surface of the engine. Now, for this procedure, I'd have two people around because it is much easier that way. So, if you hold the spark plug wire with plastic plug-wire pliers or insulated electrician's pliers, have someone turn the engine over while you hold the plug onto the metal surface. Sometimes, you won't get a spark so do it a few times until you get it for each cylinder. If you have spark, the engine should run. If you don't, it's either the individual coils that each cylinder has OR it could be the stator (not starter, just for clarification) which provides firing power for the cylinders in a basic sense of the word. Stators can sometimes be big money if you can't find a used one, which is hard to come by as well. But, start simple and replace the plug caps/wires, because it's the cheapest attempt at getting it running if it doesn't have spark, and it's probably cheap insurance in case it doesn't run after that. Good Luck!

Answer 2

Remove the spark plugs. Plug one back into a spark plug wire and by holding the rubber plug boot, place the exposed metal area of the plug firmly against some unpainted metal of the engine so there is a good electrical path. If electricity is not your personal friend, use a pair of pliers with insulated handles to hold the boot, not your hand. However, if done right, you won't get shocked.

Ignition on and turn over the engine a few times at cranking speeds. You should see a nice fat spark jump at regular intervals across the plug gap. Repeat for each cylinder. If no spark, fix. Once you have spark, onto the fuel system.

Answer 3

spark plug wet?

Answer 4

H'i     watch it!! that thunder bolt ignition will give you a real belt,,, Take out the spark plugs,leave them conected to the leads then rest one of them on the caseing and turn the engine, DON'T HOLD IT it should spark repeat with rest of plugs.If thay don't spark then your problem is fuel.