1953 Firestone 7.5/ No spark

armyhooah

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This is what I pick up for $50 bucks? Not sure if I got cleaned or got a good deal? sure you all can tell me.


What i have found is a 1953 Firestone 7.5 motor.

Good compression and no spark. Not sure where to start? Condensers or the coils?
 

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armyhooah

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Re: My new toy!!!

Re: My new toy!!!

I do not know much about outboards, any help would be appreciated.

Where is a good starting point when an engine doesn't have spark?
 

steelespike

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Re: My new toy!!!

Re: My new toy!!!

You should start by checking the compression. 100 psi is ideal and even between cyllinders.60psi is ok.A decarb treatment may improove low compression.If compression is way low could be a head gasket.Look for discoloration on head paint indicating severe over heat.Usually replacing head gasket solves this compression problem.
The Firestone was made by Scott Atwater.Best place to start is to clean and adjust the points. .020.If the coils are plastic and show any cracks,discoloration etc will need replacement.The Scott Guy at ,ask the scott guy ,may be able to help with parts sources and info.Inspect plug wires
 

sunkentreasure

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Re: My new toy!!!

Re: My new toy!!!

Your Firestone was built by Scott Atwater, so that's where you'll find service info. Google "antique outboard motor" and you'll find numerous websites. As to no spark, it could be a number of things most of which are repairable. The following applies to most old outboards that I've worked on. Scott Atwater specs might be a bit different, but this should get you going.

First of all NEVER spin the motor with the plug wires hanging freely. Since the spark has no path to ground (like the plug) this puts a tremendous strain on the secondary windings of the magneto. Always provide a small gap from the wire to the engine or just clamp it. The electricity has to "go" somewhere.

I usually remove the plugs and ground one wire. Hold the other in your hand while touching the engine with the same hand. SLOWLY spin the flywheel with the other hand. Feel a slight tingle? Good. That proves the coils may still be good and it might just be a matter of points/condenser. Check both wires this way. Sounds goofy, but it tells me that the ignition system has some life.

You'll have to pull the flywheel to gain good access to the magneteo. Replace the condensors immediately...I guarantee they're bad or close to it. Any lawnmower condensor of about 2 microfarads (most of them) should work just fine. Look at the points. Dirty? Clean them and gap to .020. If the points are eaten away replacements are still available or points from another engine can be modified to fit. Reinstall the flywheel and check your spark again, this time with the plugs outside the engine and grounded to it. Your spark should be a healthy little blue thunderclap. I'm not sure about the Scott Atwaters, but most of the older outboards had fixed timing, so that's not really an issue.

O.K....having done all that, there's another way to get the motor going (assuming the coils are good) and you'll never have to worry about it again. There are several general purpose ignition modules (about 15 bucks) sold on Ebay and other places. These little jewels will install in place of the points/condenser assembly and are solid state. A set of points is nothing more than a switch anyway, so why not replace them with something modern and trouble free? The modules are hidden under the flywheel and, unless you're a purist are quite satisfactory.
 

armyhooah

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1953 Firestone 7.5

1953 Firestone 7.5

O.K....having done all that, there's another way to get the motor going (assuming the coils are good) and you'll never have to worry about it again. There are several general purpose ignition modules (about 15 bucks) sold on Ebay and other places. These little jewels will install in place of the points/condenser assembly and are solid state. A set of points is nothing more than a switch anyway, so why not replace them with something modern and trouble free? The modules are hidden under the flywheel and, unless you're a purist are quite satisfactory.

Do you have a link or some numbers that I should be looking for?

I like the idea of something trouble free. If I am going to put the money in this engine then why not get something modern.


On a different note: To the moderators.

Why was my post moved? I put it in the right forum? OMC motor right?
 

tmcalavy

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Re: My new toy!!!

Re: My new toy!!!

Or you could keep it original/simple, service and tune it and run it for another few decades and pass it on to your kids. I bet you'll get spark after you clean up the points...you can replace all the tune-up components under the flywheel (coils/points/condensors/plug wires) for less than $100. Acme Outboards has a S-A service manual. Those are good, strong motors.
 

sunkentreasure

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Re: 1953 Firestone 7.5/ No spark

Actually, I don't. I have used at least one brand called the "Atom" module, but there are improved ones now available. Ebay seems to be the best place to find them as many small engine suppliers advertise there. Just do a search for "ignition module". Ignore all the ones that are model specific (i.e. Homelite, Briggs, etc.)....you want a general application unit, one for each spark plug, preferably with a ribbed metal case. The ad info usually states they are a replacement for almost all small engines. They're quite small and easy to install since it looks like your flywheel is off already. Just follow the instructions. The only change I've made is to solder and insulate the wire connections rather than use the wire nut they provide. I've noticed that the spark seems a bit smaller than when the regular points are used, but it is CONSISTENT which is even more important.

Another tip: after restoring your spark, clamp the motor to a support with the lower end in a five gallon bucket of water (never start an ouboard without water). Assuming the carb and fuel system haven't been examined yet, use a spray bottle of the correct gas/oil mixture and shoot a couple of sqirts into the carb. Set the controls to "start" and crank 'er over. If everything's right it should roar to life in one or two pulls. Now you know she'll run and can go through the fuel system and clean it out.

Now that you have everything set (spark, clean carb/fuel system) start it again (in water) and see if it discharges water, showing that you have cooling circulation. If there is none, shut it down immediately and find out why. Usually the impeller is shot from age or the water passages are plugged with everything from old weeds to spiders and monofiliment. You HAVE to have cooling water circulating or the poor thing will get toasted. Most outboard restorers replace the impeller right away, just to be sure.

Whew! After typing all of that, my final comment is that the Scott Atwaters were some of the nicest looking motors of the fifties. Clean and kind of sexy. Oh, you asked if you got your money's worth...definately not. They're absolute junk, so you'd better box it up and send it to me before your wife finds out you spent money on it. :D Edit: the previous poster is absolutely correct. Points and so on are available, but they may cost a bit. My solution was aimed at getting a motor running reliably when parts are hard to find. I usually save the old points and keep them in a labeled baggie for any future owners.
 

armyhooah

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Re: My new toy!!!

Re: My new toy!!!

Or you could keep it original/simple, service and tune it and run it for another few decades and pass it on to your kids. I bet you'll get spark after you clean up the points...you can replace all the tune-up components under the flywheel (coils/points/condensors/plug wires) for less than $100. Acme Outboards has a S-A service manual. Those are good, strong motors.

Not sure what I want to do with it. I like the idea of keeping it original.

Acme, I will Google them. Thanks.
 

steelespike

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Re: 1953 Firestone 7.5

Re: 1953 Firestone 7.5

OMC is Evinrude/Johnson and Gale Your motor is a Scott Atwater Thus "other outboards" posting.



On a different note: To the moderators.

Why was my post moved? I put it in the right forum? OMC motor right?[/QUOTE]
 

F_R

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Re: 1953 Firestone 7.5

Re: 1953 Firestone 7.5

To each his own I suppose. They say we all need to work to simulate the economy, so go for the solid state replacements if you want to. However, you may be able to fix it for free. The first thing to do is clean the breaker points contacts shiny bright and set the gap to .020". There is a good chance that that is all it needs.

Your picture is too fuzzy to make out just which points and condensers it has. New replacements might be available right here at iboats, depending on which ones it uses. Mercury uses similar ones.

If the coils are bad, they will have to be replaced, even if you do go for the solid state modules.
 

armyhooah

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Re: 1953 Firestone 7.5/ No spark

Yea! It has fire.

I replaced the condensers and cleaned the points. I use an automotive condenser that has very close to the same value mfd.

Next will be to see if she will fire.
 

sunkentreasure

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Re: 1953 Firestone 7.5/ No spark

Congrats! If she has fire, fuel and compression you should have a running outboard. On a final note, use the correct mix in a spray bottle if shooting into the carb. Ether is a no no......would definately cause damage.

Hey, we need more pictures too (kinda like the birth of a new baby)!
 

tmcalavy

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Re: 1953 Firestone 7.5/ No spark

Ditto...want to see that clamshell Scott running...post more pix if you can.
 

armyhooah

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Re: 1953 Firestone 7.5/ No spark

will do let me get it going first.

I just found out I am missing a part off the flywheel. Will have to wait for that then it should be a go.
 

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armyhooah

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Re: 1953 Firestone 7.5/ No spark

Anybody know where I can get the starter plate for this motor from?

It is the plate that the pull cord teeth grab to spin the flywheel.
 

tmcalavy

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Re: 1953 Firestone 7.5/ No spark

Try the free classifieds at www.aomci.org
If there is a notch in the outside edge of the flywheel, you can use a knotted rope to rope-start it...very low-tech, but that's why the notch is there in most cases.
 

armyhooah

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Re: 1953 Firestone 7.5/ No spark

There is no notch.

I wish there was, but I have to wait for the guy I bought the motor from to find it or just pay the twenty bucks for one.
 

alangf

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Re: 1953 Firestone 7.5/ No spark

Yea! It has fire.

I replaced the condensers and cleaned the points. I use an automotive condenser that has very close to the same value mfd.

Next will be to see if she will fire.
The sole purpose of the condenser it to prevent arcing and subsequent development of a "fang" on one side of the points. You can determine (if for some strange reason you want to) if the condenser is over or under capacitance according to which side of the points the fang is on. Bottom line is if the points have not developed a fang the condenser is fine. I don't replace condensers automatically. Points can also be burnished multiple times. Be sure to put a small blob of grease behind the rubbing block (the part that contacts the cam) of the points. That way, as the points wear they pick up fresh grease and stay lubricated. This will greatly increase the life of the points and allow them to maintain a proper setting for a much longer time.
 

armyhooah

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Re: 1953 Firestone 7.5/ No spark

The sole purpose of the condenser it to prevent arcing and subsequent development of a "fang" on one side of the points. You can determine (if for some strange reason you want to) if the condenser is over or under capacitance according to which side of the points the fang is on. Bottom line is if the points have not developed a fang the condenser is fine. I don't replace condensers automatically. Points can also be burnished multiple times. Be sure to put a small blob of grease behind the rubbing block (the part that contacts the cam) of the points. That way, as the points wear they pick up fresh grease and stay lubricated. This will greatly increase the life of the points and allow them to maintain a proper setting for a much longer time.

Good deal.

I will have to put some grease on them. Never though of that.

I have it running, am working on the carbs now. It will run WOT but will not idle down much past half throttle.

Will have more pictures later on today.
 

rugman65

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Re: 1953 Firestone 7.5/ No spark

I just picked one up yesterday here in indianapolis. Got it for my 14' boat
Pulled the cord and it sounded like it had good compression.Going toclean her up and she what she's got.
 
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