Evinrude Fleetwin 7.5 Spark Plug Problem

[yesizmatt]

I know a moderate amount about outboard engines and am currently fixing a 1957 evinrude fleetwin 7.5hp. I am testing the spark plugs and they spark, but were touching eachother. When I tried to see if they would spark when not touching eachother, their is no spark at all. I have never heard of this happening does anyone have any ideas on what is going on? Thanks

 

[racerone]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Sorry , you need to do a proper test.-----Make something up to force the ignition to jump a gap of 1/4".----That is the only acceptable test.----Plugs on the block is really a waste of time.

 

[HighTrim]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Have you tested the spark in general like racerone suggests? Im guessing you did, and then you wanted to check the quality of the plug and whether it was sparking?

Have the coils been changed on the motor? If not, they are NFG guaranteed and will need to be replaced.

On any new 50s OMC that I aquire, I first test compression, then pop the flywheel.

 

[boobie]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

You can buy an adjustable open air gap spark tester at any parts house for around $8.00. Set it at 1/4".

 

[oldboat1]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

That's a sweet motor. I've had a few of them, and currently have one that I'll use this spring (if the ice melts). Mine will be due for an impeller, which means powerhead removal [open to a better way, btw, if other listers have one to offer up] -- need to disconnect the shift rod connector to drop the lower unit. When you get to it, the mix on your motor is 16:1, and runs well on that (J4C plugs gapped to .030.) Points are gapped at .020. I typically just replace points and condensers, and usually coils. If your coils are cracked they are on their last legs -- can test them, but again I usually just replace them. All the magneto parts are readily available (about $130 total, incl an impeller). Good project.

 

[yesizmatt]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

I have re tested the spark plugs and both of them produce a solid blue spark which I believe is what you want to have. I also believe the coils have never been replaced but I don't think they need to be as it makes the spark plugs create a spark now. The problem with the motor is that it does not run as fast as it should, and sometimes just dies out. I thought that it was from maybe running on only one cylinder but now I do not now what would be wrong.

 

[nwcove]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

as mentioned, the fact that the plugs make a nice spark when removed from the engine doesnt mean they will under compression. you need to test as recommended. ( open air tester set at 1/4"). take the teardrop shaped cover off the top of the flywheel and have a look!

 

[racerone]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Not sure why folks balk at doing a proper test based on facts !!!----Your spark is no good if it will not jump a gap of 1/4" or more !

 

[nwcove]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

the coil in the pic i posted would make a spark at the plug, but !! lol

 

[boobie]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Checking the spark with the spark plugs is useless. Won't tell you a thing.

 

[HighTrim]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

...and to add to good advice above, even if the coil produces spark, but is original, just toss the darn thing. It WILL fail on the water when warm, I guarantee it. Unless you like to paddle

 

[yesizmatt]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

I opened up the teardrop shaped plate on the top of the plate, and sure enough, I can see cracks on both of the coils. Looks like that is the problem to why my motor dies out and does not go as fast as it should? And is replacing the coils a hard process to do or is it fairly easy?

 

[HighTrim]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Fairly easy.

There is a good thread in the Top Secret Files that should help with pics.

 

[yesizmatt]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Well it looks like I am going to purchase new coils. Is their a specific type I have to get and where can I get them from? I have never replaced anything like this before.

Thanks for all the help so far!

 

[Greg O.]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

I love my 7.5 fleetwin, great little motor. The coils might be working fine at lower speeds, and not so well at high speed. The secondary windings in the coils break down with time and might even have a break in the wire. The spark can jump the break in the wire till the gap becomes to large. I would replace the coils. Here is a youtube video that illistrates how to test coils. How to test a coil in an antique outboard engine - YouTube

 

[Greg O.]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Right here on Iboats the coils are available.

 

[Greg O.]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Ignition Coil for Johnson/Evinrude 582995 584477, Mercury/Mariner 802371A1, GLM 72100 - Sierra

 

[yesizmatt]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

thanks!

 

[yesizmatt]

Re: Evinrude Fleetwin 7.5 Spark Plug Problem

Do you think I will be ok with just purchasing the coils you linked me or will I need to get new points and new wires aswell?