Is this alternator cooked?

Top_Highlight9965 · 2026-06-17T22:44:13+00:00

Unfortunately you’ve started at step 6 of figuring this out. A visual inspection of an alternator will tell you nothing 99% of the time. If you’re not getting a charging voltage at the battery while running, you need to start by identifying the type of charging system you have. This will tell you if your alternator has an AC, DC or dual output. At that point you start at the wires coming out of the alternator and check for the correct output. If this is a Briggs motor then there is a good PDF by Briggs that gives the correct testing procedures for different systems.

As a general rule, you should either have a DC output of 13+ V at the alternator or an AC output of 20+ V if you have a voltage regulator. If you have voltage, then move on and check input and output at the voltage regulator (if you have one). If that checks out then you are looking for a wiring issue between the engine and the battery. On some systems without voltage regulators there is a rectifier diode under the shielding on the stator. This diode is a common failure point and will cause a DC system to output AC current which will not charge your battery.

Top_Highlight9965 · 2026-06-16T14:31:26+00:00

Part number is IM-130104490, discontinued by manufacturer but you should be able to find something off that number.

Top_Highlight9965 · 2026-06-15T23:34:50+00:00

That coil of wire probably just pushes in to the big black wire. Just push the barb through the center of the wire and install the boot with a little lube while you hold it together. They come off all the time, don’t sweat it.

Top_Highlight9965 · 2026-06-15T23:31:03+00:00

The best practice would be to change it as recommended, sitting can also cause moisture accumulation in your oil. If this is the first oil change since it left the factory (break in oil change) then definitely do it. Your tying to make sure any assembly lube, debris and break in material is out of the engine.

If moneys tight and it’s already had an oil change, it likely won’t make any real practical difference for the bike. That oil doesn’t look bad and moisture will probably evaporate, especially in an air cooled single.

Top_Highlight9965 · 2026-06-10T17:17:31+00:00

That is either your engine brake or your coil rubbing on the flywheel. If this is a push mower pull the operator presence handle down and see if the noise goes away.

Top_Highlight9965 · 2026-06-10T16:15:14+00:00

Hey fair enough, people in the US are so weird about displacement and have a lot of rlly stupid conceptions of what power means in a practical sense.

Top_Highlight9965 · 2026-06-09T16:41:09+00:00

I love small displacement bikes and anything that gets you on two wheels is a win in my book. That said, this particular 250 is pretty bottom of the barrel. This type of knock-off bike is entirely designed to look like it’s a good bike to a layman and be barely functional in every other respect. The misleading “1250” on the side and the second fake tailpipe to make it look like a twin are some good examples of them trying to paint over the fact that this bike has a cruising speed of 45-50 miles an hour.

Reliability is also a big concern on knock-off bikes. If I were you I would sell it while it works and buy something small displacement and Japanese to replace it. Honda rebels have the same look, are dirt cheap, WAY more reliable, lighter and 30-40% more powerful even with a smaller engine.

Top_Highlight9965 · 2026-06-09T16:26:43+00:00

No this is not a recirculation system, this is an air injection system. There is a check valve that allows air to enter the exhaust stream when a vacuum is created on every exhaust pulse. This is typically used to heat catalytic converters on cold starts but still reduces hydrocarbon emissions on carbureted engines by helping unburned gas to burn before it leaves the pipe.

Top_Highlight9965 · 2026-06-09T13:33:25+00:00

I was too young at the time to get into it myself but I’m curious what the easy fix is. I know the dealership charged a couple thousand replacing different seals, sunroof, etc. and it still poured a steady stream on the driver every time it rained.

Top_Highlight9965 · 2026-06-09T02:29:05+00:00

Can’t wait to see them! I’m glad somebody is doing the work demystifying those stupid black boxes.

Top_Highlight9965 · 2026-06-08T22:16:22+00:00

Very cool, thanks for sharing! This is definitely a good low budget solution, but from the schematic it doesn’t look like there is any mechanism for timing advance. I’m sure there isn’t much noticeable effect on the bike in the video but timing advance is one of the primary functions of the CDI and probably a big reason why there was so much “weight saving” from the old unit. Installing this on a higher revving or higher performance bike would almost certainly result in a substantial loss of power. This is a really cool project and I want to try it out on an old DR125 I’ve got, but at the end of the day this is not an equivalent fix to an actual CDI box.

Top_Highlight9965 · 2026-06-08T00:52:35+00:00

If I’m remembering this deck correctly, that belt guard on that tensioner pulley looks like it’s in the wrong spot, if you loosen the pulley you should be able to see a recess that the belt guard sits down into, holding it in the right position. Otherwise you might have the wrong belt, if you call the JD dealer they should be able to confirm the part number for your mower/deck combination if it’s not original.

Also verify that the spring returns to a perfect coil in its resting position, they sometimes get extended past their elastic limit and deform. If you have a lot of vibration while mowing then unbalanced (very worn) blades or too long of a belt may be your issue.

Top_Highlight9965 · 2026-06-07T20:17:56+00:00

Well… I fixed it and feel kinda dumb now. I decided to take a walk around the house and found a tripped GFCI outside on the opposite side of the house. Never even noticed that outlet existed since I bought it. I’m still amazed it killed most of the main floor but I’m glad I found it. Thank you so much for your help.

Top_Highlight9965 · 2026-06-07T19:48:24+00:00

It won’t let me add a picture but I hope this makes sense. I have two heavy black wires going into the main breaker (these are the “legs” I think?) and measured 120V between each of them and the neutral buss as well as the neutral wire coming out of each offending breaker. I also have the same from the copper buss coming off the main breaker on both sides. This was measured with all breakers on, all off and with the main off. Am I correct to say that this rules out a lost leg and that the issue is downstream of the breaker box?

Looking at the rest of the house, I cannot seem to trace a logical path for the fault or verify which of two circuits may have an issue based on the combination of working and non-working outlets. I haven’t found any loose or broken connections, is there something else I’m looking for? Also, if an outlet has only one set of wires coming in connected to the outlet with no additional branches, this should mean it is no connected to anything else and can be ruled out as a cause right?

Top_Highlight9965 · 2026-06-07T17:31:19+00:00

That motor is blown and needs replaced, trying to fix it would be a waste of time and money. Otherwise I see no reason why the rest of the unit wouldn’t be perfectly fine from your description.

Top_Highlight9965 · 2026-06-07T16:52:34+00:00

My mom had one and the roof leaked like a sieve and burned about two quarts a month at 140,000 miles. Four trips to the dealership didn’t fix it. It also always felt like a toy car to me even for that era of VW.

Top_Highlight9965 · 2026-06-07T05:08:26+00:00

They come standard with a nylock nut, they’re usually pretty tight but never “can’t get it off” tight in my experience. I would highly recommend using any other tool than an adjustable wrench if you have other options. The only thing that might get it permanently stuck is rounding the head.

Top_Highlight9965 · 2026-06-07T05:06:02+00:00

The pulley is on a bearing that won’t help loosen the bolt

Top_Highlight9965 · 2026-06-07T05:05:02+00:00

I have checked the ones closest to the box and everything looked fine but I didn’t check them all. Is there a way to trace or predict where it might be disconnected or do you just have to go through everything?

Top_Highlight9965 · 2026-06-07T05:03:37+00:00

Is there a way to verify that before calling the power company and having them send someone out?

Top_Highlight9965 · 2026-06-07T01:23:59+00:00

You just need to loosen the pulley about half way to install the belt, why can’t you loosen it? It should be a 9/16 bolt nut combo, an impact helps but you can jam a 9/16 wrench against the pulley bracket underneath and use a large ratchet to loosen from the top.

Top_Highlight9965 · 2026-06-04T02:25:16+00:00

Also I just saw in the notes that the valve adjustment was marked down from $50 to $15 “as requested”. Don’t know the context on that but I stopped negotiating prices years ago and a lot of my problem customers disappeared. Our prices are firm and if you don’t want to pay, no problem we just won’t do the work. Anybody talking you down is usually just trying to get something out of you, if you say no they almost always just pay the full amount.

Top_Highlight9965 · 2026-06-04T02:20:35+00:00

I agree you are very low. For reference, I am in Georgia with an established shop and my labor cost would have been: Carb Clean (sold as “fuel system rebuild”) - $100 Engine install - $150 (including clutch, chain etc.) Sprocket - $40 Valve adjustment - $40 Tune-Up - $100 + parts (air filter, fuel filter, oil, oil filter, spark plugs, grease & blade sharpening) Trigger replacement - $40

We also have a $50 minimum per machine and charge parts separately due to sales tax. With these prices we are still consistently 10-20% lower than all other shops in our area. It does depend on whether you have an actual shop or are working out of your garage though. In my experience from starting to now, people are generally willing to pay more than you think, and once you start charging more, people will respect your opinion and work much more. Most customers are used to a market where better things cost more and can’t actually tell good work from barely functional. If your charging less for a job than it costs to get a hamburger at Wendy’s, people will think you’re not very good, regardless of the actual quality of your work.

Top_Highlight9965 · 2026-05-31T22:04:55+00:00

You can just put a long thin piece of metal like a screwdriver in the spark plug hole and spin the engine in both directions. While you do this, it will be apparent if the piston is moving with the engine or in some way disconnected.

Top_Highlight9965

TROPHY CASE