Ignition Coil

[181Mariah]

Looking for a coil for a 1993 4.3LX Merc, part number 18-5439. Do they sell these at the local auto parts stores?

 

[searay3]

Re: Ignition Coil

The coil is not marine specific. Some choose the epoxy filled. I have used the oil filled (mallory blaster) for years. No issues. You will need the electronic ign type though as you have that type of ignition, full 12 volts input.

 

[181Mariah]

Re: Ignition Coil

Thanks searay3,
It says Thunderbolt Ign on the air cleaner lid, is that what you are talking about?
I have had the boat for 2 weeks now and taken it out 4 times. The boat first starts off fine (4300 RPMS) and then starts cutting out to 3000RPMS after a minute or so. If you stop and idle for a minute it will start back and run good again for a minute again. The last time I took it out it was running better and then the starter sounded like it was jumping on the flywheel. I got it started and made it to the dock. There is black shoot on the rear of the boat like it is running rich. The previous owner changed the plugs, fuel pump and filter.
I am going to pull the plugs to see if they are fouled. I think this is why the starter seems to be jumping teeth. I had the starter checked last weekend and it is fine.

 

[searay3]

Re: Ignition Coil

Black soot usually is telling you it's overfueling. If carbed, check the choke operation and setting. There are free manuals at the top of the forum. Check to see of your is available. Then start looking at the carb. I'm with you though, make sure the ignition is up to snuff before tearing into the fuel system. Seen it many times, carb wasn;t the issue. If the boat is new to you, start with a complete tuneup. Plugs/wires/cap/rotor, fuel and water seperating filter if you have one. It's a 93, who knows how old the stuff is...

 

[180shabah]

Re: Ignition Coil

Test the coil before you just buy a new one - this is a pretty expensive method of problem solving. All the specs are in the manuals available for download at the top of the forum.

Ditto the black soot pointing to a rich condition - I would start with the choke. Is it electric? If so, is it geting voltage? If it is not electric, you need to take some measurements and compare to the specs in the manual.

Are you seeing a pattern here - there is no substitute for a Factory Service Manual.

 

[searay3]

Re: Ignition Coil

All due respect...Coil, plug wires, plugs, any of the consumables on a 17 year old boat I do not consider expensive. A coil around here is 30 bucks. It also gets the wires and connections a good going over while your there. The IGN module that runs 400 bucks I would test. No question. Other components of that age get replaced. Just my opinion....

 

[181Mariah]

Re: Ignition Coil

On the last run in the boat the throttle would only move half way down and the boat would not plan out. I found the linkage was sticking on the prot side of the carb, I then flipped over the part that was blocking the main throttle. This fixed the problem with the shift cable but I am not sure which way it is suppose to go. After I turned off the engine and tried to restart that is when the starter was jumping. I am thinking I fouled the plugs because of the black shoot on the rear of the boat.
I am going to go thru all electrical to make sure that is not the problem. It is cheaper than a carb rebuild and fuel pump.
It has the Weber 4 barrel carb with vacuum choke. The boat has 237 hours on it, that would be 14 hours a year. The boat must have sat up for a while. I may go pull the plugs tonight if it cools down some. I am in Texas and it has been hot down here.

 

[181Mariah]

Re: Ignition Coil

Just got back from the boat storage. Took off dist and in was very bad. Plulled the spark plugs and 4 were cracked, two were set at .10, two were set .20,two were at .30 and one broke off when I pulled the plug wire. Will fix it Friday and let you know how it runs then.

 

[180shabah]

Re: Ignition Coil

Neglect is the NUMBER 1 reason for poor performance.

 

[wca_tim]

Re: Ignition Coil

Neglect is the NUMBER 1 reason for poor performance.

AMEN to THAT!!!

 

[wca_tim]

Re: Ignition Coil

Just got back from the boat storage. Took off dist and in was very bad. Plulled the spark plugs and 4 were cracked, two were set at .10, two were set .20,two were at .30 and one broke off when I pulled the plug wire. Will fix it Friday and let you know how it runs then.

that's rough! while you;re at it, if you're not already planning to do so, a carb kit might be in order too...