Roll call for 125 mods at Huntington

[Smiley]

I stand corrected.. If you use the normal kill switch we all use, you will still need an on off switch from the power source to the blue wire. Current continues to flow to the controller. We tested today. Motor ran fine but we were unable to get on plane. According to Howard Pickerell in a phone conversation this evening he said. You are almost there. Too much blade area and or too short a diameter. Assuming you are using two blade round blades like Smith, start reducing blade area from the tip downward along the leading edge toward the hub to unload the prop yet keeping the pitch at the end around 8 inches. Eventually you will have a modified cleaver looking prop. That will wind up, the motor is unloaded and the speeds are up. Here are a couple more hints he offered. The carburator fuel inlet needs to be rotated so the the inlet is up between say 10-2 o'clock. This will allow fuel to cover the diaphram and priming and starting will be much easier. Also when setting up the throttle. Put no more than sufficient pressure on the throttle linkage so the throttle stays open and no more. The throttle linkage is made of brass and is soft. Be aware of this so you do not twist and break it. I also noted that when you look into the carb inlet the full throttle linkage has the butterfly slightly over center. Carefully bending the throttle arm might recenter the butterfly. Howard further stressed the hi quality kill switch previously mentioned for reliability. I have found my kill switch to be unreliable. Sometimes works, sometimes not.

[Smiley]

Tried the circuit this am. Hoooraayl all is well. Nice fat blue spark. gluing the wire to the crankcase offers a strain relief for the wire also and prevents engine vibration from wearing through the insulation. Think how airplane wiring is laced, bundled to prevent vibration, rubbing and flexing hour after hour. You do not want a component failure at 14,000 feet. Could ruin your day or in our case a lost win at the nationals etc. So it is a go for testing with Bob Wartinger soon.
Bob Smiley 68R.

If you get the normally closed kill switch you do not need the toggle switch for power on/off. You must remember to pull the clip off after each run. That is your switch that breaks the circuit. Howard Pickerell suggests we purchase the merc crusier performance engine kill switch. A high quality spendy kill switch that is closed when you have the clip on and open when the clip is removed. It is flush mounted with two mounting holes. His reason for this particular switch is that it is very dependable and will not fail like the cheap ones we use. He runs a lot on salt water. Cost is about $60.

[GrandpaRacer]

I put my standard Normally Open kill switch between that trigger wire and ground. You proved it works there too! John

[bmitch1]

I had to watch that closely too... good point for a guide... glad you tracked it down!

[Smiley]

I believe I found the problem. I thought it was the CDI that failed. Upon closer look the trigger wire from the hall affect sensor appeared to be crushed between the crankcase and the adaptor to the OMC midsection. Upon teardown that suspicion was confirmed and the wire was grounded to the crankcase. I assume a little silicone and perhaps glueing the wire to the crankcase so it does not migrate between metal parts again, reassemble and all should be OK. Will do this task Father's day pm. Tonight I can rest easy.

Guys, make note of this easy possible mistake. Could save much grief and time.

Bob Smiley

[modhydro]

Do you disconnect the kill switch and put a jumper between the two leads? We had one run at Huntington and then not spark. It turned out to be the kill switch. No changes to anything, just quit working.....

[modhydro]

The users guide is in process. Right now we just have some notes that have been shared. I will try to get a draft of what we have so far posted this week.

[Roskowski30h]

Check the boot to your spark plug wire. It should basically screw on the end to make contact. I'm not super confident that makes for a good connection especially with how much they vibrate, it sounds like something is almost makign the complete connection, but not quite

[GrandpaRacer]

Try turning it over with a battery powered drill. Put a nut on the top of the drive shaft and use a socket in your drill to spin it. With the main power turned ON and no load from the starter motor, if you get spark while turning with the drill it suggests your battery is too weak to run the starter and the CDI box at the same time.

[Smiley]

Thanks for the comments above.

1. did that
2. Battery was not fully charged. It now is and is on float.
3. Checked ground was OK previously but it is not common. Good idea to do it.
4. Motor was run in the barrel and it was not disassembled so the trigger wire is ok
5. That is the last resort. I need to purchase a coil and brain box. If one is bad then I have a spare for the other part, else I have two of each that is serviceable. I sense that the brain box may be bad if 2 above is not the culprit.

can you imagine you travel across the country like to Moses Lake this July and your coil or CDI fails? Carry a spare and a good VOM meter guys. Could save your vacation.

Also need to get some start washers.

OK I did the following

Everything connected. When I jumpered across step one above the spark plug arched. when I do it several times it does not spark but occassionally it will spark????? Turning the motor over to start it. No luck??

[DeanFHobart]

A few things to try:

1) Remove the arming microswitch from the circuit and put a jumper in its place to make sure your kill switch is in a running state.
2) Make sure your battery is at full charge
3) Double check to make sure your coil is grounded (I missed this and had no spark initially). I have a common ground for all electronics on mine and it seems to work fine
4) Make sure you your crank position sensor wire did not get damaged when you put it on whatever tower you are running
5) Try to swap the brainbox/starter unit with parts off another engine if possible to see if the problem lies in the box or the coil. I had a bad coil that gave one weak spark which we think gave some sort of feedback to the brainbox which caused it not to spark. We had to swap brainboxes and coils to get spark then switch back to the original brain box and finally got spark.

I hope something in there helps, let me know if any of that fixes your issue. I really want to see this class succeed.

Kyle

You bet.... we need this class to succeed. I’m sure new motors come with a manual... Is this true?

Just a suggestion........ The Mod Commission or someone needs to make a ‘Tip Sheet’ or manual for our application. We have additional requirements than the Kart group does. Pictures included to go along with the written description.

[GrandpaRacer]

Another thing is to always use star washers (i like internal ones) on all ground connections. This provides a gas tight good electrical contact.

[Roskowski30h]

A few things to try:

1) Remove the arming microswitch from the circuit and put a jumper in its place to make sure your kill switch is in a running state.
2) Make sure your battery is at full charge
3) Double check to make sure your coil is grounded (I missed this and had no spark initially). I have a common ground for all electronics on mine and it seems to work fine
4) Make sure you your crank position sensor wire did not get damaged when you put it on whatever tower you are running
5) Try to swap the brainbox/starter unit with parts off another engine if possible to see if the problem lies in the box or the coil. I had a bad coil that gave one weak spark which we think gave some sort of feedback to the brainbox which caused it not to spark. We had to swap brainboxes and coils to get spark then switch back to the original brain box and finally got spark.

I hope something in there helps, let me know if any of that fixes your issue. I really want to see this class succeed.

Kyle

[Smiley]

Well, We tried to get on the water Friday. No luck. No spark. Wiring is proper but with or without the kill switch on or off, no luck. The kill switch is the normal one we use which I later discovered is just opposite of what we need. Pulling the key made no difference. The switch was on in the garage overnight providing power to the CDI, battery discharged, charged up the battery with all wires connected with a 12 volt charger. Is it possible that too may amps were input and affected the CDI? Do not know if the CDI or trigger failed. VOM showed no discontinuity in the harness or connections. All grounds were secure. John Adams suggested supplying a battery and arc it to simulate a trigger and look for a spark. Tried with 1.5 volts. no success. Any other ideas would be welcome. Does anyone know what reading with a VOM are standard on a working CDI?

Also following up on my last posting. the holes for the shear pin were reamed out by inserting the reamer in the hole, attached the hand drill and pulled the reamer backwards into the prop. When cutters were in both sides of the prop, held it there for a few seconds them removed the reamer. The holes are straight and true.

Bob Smiley 68R

[GrandpaRacer]

We saw low 50s too with zero prop testing. Our motor ran good once I replaced the little micro switch and moved it from the saddle to the boat. Too much vibration caused the switch to turn off!