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01 mercury 40hp 2 stroke 3 cylinder running half speed

C

carjo40hp

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I am new to boating. Just bought my first boat. Its a 18ft 2000 model pontoon boat. Took it out was first time and it was having trouble idling. The guy I bought it from said it was last year's gas that was in it. Got it away from the dock it was running good then it started running about half speed. I thought maybe the trotle cable slipped or something. Figured out that wasn't the problem. The guy also mentioned he didn't change the plugs so the next day i changed all 3 plugs and took it back to the lake. Idled a little better but still only running about half speed. When changing the plugs the top cylinder wire looked as if it was cut up some so was driving the boat i pulled the top off to see if it was arcing. Couldn't see it arcing but it did shock me. I got it home and pulled the plugs and the top plug looked new still and that was the wire that shocked me. So i ordered another coil pack. But after reading a bunch i checked to see if the plugs were sparking and all were still sparking. So now I aint for sure the coil is bad just because I got shocked. Any ideas. Hope i didn't buy a basket case. Dont have alot of money
 
You certainly shouldn't get a shock from anything you touch on an engine. you probably got the shock from that HT wire to your plug and the only reason it sparked is that when you pulled out the plug to check it, the internal core of the wire rejoined itself allowing a spark to occur. You will have a break in that HT line from your coil to the plug, replace that and your engine should run better.
One other thing when buying a boat is that the seller wants to sell so will tell you anything. Don't always believe what he says!!!
By all means flush out the tank and replace with new fuel also add a little carburettor cleaner as the oil added to 2 stroke engines can clog up the valves after standing for a long time. Ensure there is a good jet of water out of the "pe pe" pipe and that after running for a while feel the top of the leg for over heating, if you get the chance replace the oil in the gear box by the prop shaft, this is always overlooked by owners.

When I buy an old engine for my own use there are a few things I ALWAYS do which don't add up to a lot of money but give you piece of mind.. First, new plugs, second, new impeller, third clean tank and flush through carburettor with carb cleaner, forth, replace gear oil, fifth, spray all electrical components and wires with electrical cleaner and preservative -- WD40 or the like. and finally start up engine and check all parts for overheating.
 
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Eric Hoare said:
You certainly shouldn't get a shock from anything you touch on an engine. you probably got the shock from that HT wire to your plug and the only reason it sparked is that when you pulled out the plug to check it, the internal core of the wire rejoined itself allowing a spark to occur. You will have a break in that HT line from your coil to the plug, replace that and your engine should run better.
One other thing when buying a boat is that the seller wants to sell so will tell you anything. Don't always believe what he says!!!
By all means flush out the tank and replace with new fuel also add a little carburettor cleaner as the oil added to 2 stroke engines can clog up the valves after standing for a long time. Ensure there is a good jet of water out of the "pe pe" pipe and that after running for a while feel the top of the leg for over heating, if you get the chance replace the oil in the gear box by the prop shaft, this is always overlooked by owners.
Click to expand...

So can the coil still be bad even though the spark plug still sparks when placed against the head. I pulled 1 wire at a time to see if the motor had any change. I read that is how you can test to see if the coil was bad. Really didnt notice much change until the last wire was pulled then the motor just died. But like I said I saw spark on all 3 spark plugs from every coil. I know the 1 needed to be replaced because you shouldn't get shocked through the insulation of the wire. But will the spark plug still spark even if the coil is bad and the insulation has a hole. Weak spark cause a cylinder not to fire. I guess I am just hoping it is just the coil
 
As with cars HT leads can break down inside which give weak of no sparks, if the wire is broken inside it may still work a little as a spark can jump across the break and even spark at the plug at the same time but the spark will be weak which does not ignite the fuel properly. Do you plug leads go directly into your coils or are they connected to the coil by a male/female socket. Coils are pretty tough and do not often break down but the leads do.
regards Eric
 
The plug wire goes into the coil. I believe its one piece. I pulled on the plug wire couldn't get it out of the coil. Didn't want to rip it out. I ordered a new coil on ebay and it shows the coil and wire as one piece
 
The bottom 2 coils have the same number on the side. The top 1 had a different number kinda seems like maybe someone already replaced the bottom 2 and not the top 1 which is the 1 in question
 
which plug did you pull off when your engine died?

If it was one of the bottom two then the engine would die as it cannot run on one cylinder which would say that the fault is defiantly the top coil/plug lead that is the faulty one. When will the new coil arrive???
 
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Eric Hoare said:
which plug did you pull off when your engine died?

If it was one of the bottom two then the engine would die as it cannot run on one cylinder which would say that the fault is defiantly the top coil/plug lead that is the faulty one. When will the new coil arrive???
Click to expand...

Yeah it was the bottom plug wire that killed the engine while it was running. And my new coil should be here by this weekend. I plan on buying some seafoam to mix with the gas and throwing the new coil on it and crossing my fingers. Hope it runs more than half speed
 
I hope it sorts out your problem anyway and gives you years of fantastic boating experiences but never under estimate the power of water as it can be your best friend or your worst enemy. Respect it and you will be fine.
Best of luck from the UK
 
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