1976 25 hp Points question

[69 Alumacraft]

About to pull flywheel, engine runs well at low speeds but will not plane out, rebuilt carb and tested coils so now digging into points and coils, I think I have a grasp on gapping points but not "cleaning" them. I have read that even a finger print will impede operation so ; How does one "clean" points? Any info input appreciated and yes I have looked at top secret files in detail and searched other posts. Thanks

 

[CatfishMN]

Re: 1976 25 hp Points question

Hi. Wondering why you are jumping to the points as the fix to this problem? Do you suspect a cylinder of dropping and not letting you get on a plane?

As far as cleaning, you can file them, but you may be better off replacing.

 

[F_R]

Re: 1976 25 hp Points question

First look at them. Points that have been run will have a frosty appearance where they make contact, and the contact area should be like half the total face or smaller. If the are frosted over the whole area, or the faces are not smooth, or the "frost" looks contaminated or dirty, clean them.

Best way to clean points is to take them apart and polish each contact individually. Use a strip of 400 grit (black) sandpaper, backed up with a strip of something such as a hacksaw blade, and polish them shiny bright. Make sure you remove all grit that may be left behind.

After reassembled and gapped, the last step is to pull a piece of clean, plain, paper between them to remove the last bit of whatever (yes fingerprints). Don't pull the paper all the way out because it may leave a bit of lint from the edge of the paper. Pull it a way and then open the points to release it. Last step is check the resistance with an ohm meter. Should be zero resistance. Not just low resistance, zero. Actually, if you got them clean as just explained, they will pass the resistance test.

Degrease them first if greasy our oily.

 

[69 Alumacraft]

Re: 1976 25 hp Points question

I have 2 motors a 1969 25 hp rude and a 76 25 hp rude. The 76 ran great for me for about 1/2 a season then just bogged out and would not run one day, if I put new plugs in it would run for a while and then foul the plugs and start missing. I have had both carbs apart and cleaned and rebuilt, they both work well on the 69 but neither will allow the 76 to plane out just run at low speeds (extremely smoothly BTW). The 76 has newer looking coils and I used and ohm meter to check continuity from coil to spark plug and both checked out so I can only assume the problem is under the flywheel right? Or am I missing something? I also replaced the fuel pump but still no top end. Any advice , feedback appreciated.

 

[liz873]

Re: 1976 25 hp Points question

If fuel delivery and compression arent the prob check timing and ignition sytem. You said you checked coil for resistance. You need to take two readings one for primary and one for secondary. Need to take flywheel off. What were the readings? Also condensors can be bad. If you remove your flywheel check the plate underneath for any play. This can upset timing. I just had a crash course using the ohms meter on my 1972 johnson but i finally understand it now.

 

[Tim Frank]

Re: 1976 25 hp Points question

The 76 has newer looking coils and I used and ohm meter to check continuity from coil to spark plug and both checked out so I can only assume the problem is under the flywheel right? Or am I missing something?

How did you check coil w/o removing flywheel?
I must be missing something.

Any chance this is a later model with coils that are not underneath the flywheel?
In that case it may not be a '76, (this is why you should always quote model number) and you may not HAVE points.

 

[F_R]

Re: 1976 25 hp Points question

A 1976 has the Lo-Tension Magneto. Two externally mounted spark coils, and a driver coil under the flywheel. Two sets of Points and two condensers.

Points are the most common problem with them. BOTH sets of points have to be right in order for it to run. Unlike the older models where it can run on one cylinder if only one set of points is bad.

 

[kbait]

Re: 1976 25 hp Points question

I believe pre-'74 had under-flywheel points, '74-'76 had points and external coils, and '77+ had cd ignition..

 

[69 Alumacraft]

Re: 1976 25 hp Points question

Like I said i also have a 69 sportster w/ no external coils, the 76 has two external coils. Does this mean I have internal coils as well. It runs great at idle but once I go past 1/3 throttle it bogs, I know it is not the carb or fuel pump and the external coils look good b/c the fuel pump is brand new and the carb has been rebuilt and works fine on my 69. I used an ohm meter to "test" them for continuity I think by attaching one end of the meter to the ground or black wire on the coil and the other to the wire inside the spark plug boot. I have not checked compression (have to buy a tester), but assume the points/ condensers may be the culprit. But it does run well at idle and slow speed so am I barking up the wrong tree? Once again I bought this motor and it ran great all summer and died in the fall suddenly. It is pushing a 1970 14ft alumacraft so not getting overworked. So if I understand you F_R it cannot be the points since it runs?

 

[scanman]

Re: 1976 25 hp Points question

I just rebuilt my '76, 9.9 with the same external coils. You have what I call a "driver pack" mounted under the flywheel. It uses the magnets in the flywheel to create the potential to make a spark when the points close. It kinda sounds to me like a set of points may have corroded or rusted between the block & the points themselves. I removed my points, cleaned the mounting holes & screws with a wire wheel in my dremel tool, & remounted them. It made a world of difference in idle speed, WOT, & throughout the RPM range. It even helped with the transition from idle to WOT. It's a lot "smoother" from low to high. Definately clean the contacts while you are in there, but don't overlook thier connection to the block! I pulled my flywheel FIVE TIMES lookin for this problem!!!!!!! A fellow iboats member helped me find this!

 

[scanman]

Re: 1976 25 hp Points question

Also make sure of the connection between the "driver pack" & the block.

 

[F_R]

Re: 1976 25 hp Points question

No, I was pointing out that one set of points CAN kill the whole thing. Not necessarily that it WILL.

As somebody already explained, the coil under the flywheel generates the electricity for the ignition system. That is done by the primary winding in conventional coils that are under the flywheel. It's a long story. Even I have to ponder on it to understand.....every time I think about it. Sometimes I'd rather not think about it.

 

[Tim Frank]

Re: 1976 25 hp Points question

A 1976 has the Lo-Tension Magneto. Two externally mounted spark coils, and a driver coil under the flywheel. Two sets of Points and two condensers.

Points are the most common problem with them. BOTH sets of points have to be right in order for it to run. Unlike the older models where it can run on one cylinder if only one set of points is bad.

I believe pre-'74 had under-flywheel points, '74-'76 had points and external coils, and '77+ had cd ignition..

So was '76 sort of a "bridge" year, 1/2 way between straight magneto ignition and CD? Kind of a one-off?

 

[69 Alumacraft]

Re: 1976 25 hp Points question

Thanks guys, I'll be getting into it over the next couple of weeks and keep you posted and of course ask more questions, my plan was to tackle this motor and then do the points on my 69 sportster, but it appears I am working w/ 2 different animals here. My goal is to have two fully operational 25 hp. Anybody have a suggestion about where to get the 1/4 fine thread Grade 8 bolts to pull the fly wheel, I rented a 32 piece harmonic balancer puller but of course it does not have the bolts I need, Home Depot or ADAP?

 

[AlTn]

Re: 1976 25 hp Points question

1/4" x 20 thread..you'll need grade 8 washers as well....thread needs to penetrate f/w 7/16" or so...HD or the auto parts joints should have them

 

[OptsyEagle]

Re: 1976 25 hp Points question

It seems to me that we are way ahead on this problem. All we know is the motor seems to idle OK but bogs down at higher throttles. If it were me, I would first do an external spark test and see if the ignition can jump a 7/16" gap on both cylinders. If a cylinder was dead I would then swtich the coils and do it again. If the dead cylinder moved with the coil then I have probably isolated the problem to that coil. If it didn't move, the problem is probably under the flywheel. Or maybe both cylinders are firing fine.

I would also start the motor and at idle pull each spark plug boot to see if the motor still runs on the other cylinder ( it should) or if in fact that cylinder is dead. Obviously if the spark test showed a dead cylinder this test would be mute, but if it didn't and this test did, then it would indicate to me that something other then direct spark might be causing this problem.

These are basic tests that I would do before I started pulling flywheels. By the way, is it safe to assume you are using Champion J4C spark plugs?

 

[69 Alumacraft]

Re: 1976 25 hp Points question

model # 25602E 25 hp 1976 Yes j4cs properly gapped, pulled flywheel points and condensers appear new or newer , "driver coil" is scuffed up on one corner which tells me it was not remounted properly and flywheel scraped it up, next step is to test coil, regap and clean points and put back togehter (torquing flywheel nut to 40-45 lb of course) pics to follow for those interested. All help comments, ideas greatly appreciated.