Jabiru problem

[hendonguy]

i have an interesting problem with me 2200 solid lifter engine ,

 

i am a qualified mechanic with more years than i would like to admit but I think i need some advise .

 

we blew our jabiru up which caused a heap of damage , i stripped the engine and very carefully rebuilt

 

using replacment parts from jabiru

 

heres the problem ,only one mag has spark

 

i have swapped one thing at a time from the good ignition ,

 

first i changed the rotor still no spark on the bad one but still spark on the good one

 

i put the rotor onto the shaft and fitted the cap allowing it to push the rotor to the height , that didnt work so measured the good one and set to same no good ,

 

i changed the coils good one still sparked but still on good on bad ,

 

i tool the distributor cap off and wound the engine to check the shaft was straight and turning all ok ,

 

changed the cap over ,still great spark on the good one bad one still no good

 

i disconnected the earth /kill wires still no good , i changed spark plus no good

 

plug leads no good ,

 

as everthing has been taken off the good one and swap but dosent work on the bad one

 

the engine runs

 

but i have a second problem the engine will only run on 3 cylinders and only runs with choke full on

 

the cylinder that dosnt go, has plenty of compression , i think this problem may be an air leak in the intake but the no spark is puzzling anybody got any ideas ?

 

 

[brilin_air]

Did you take the earth wires off the coils or just disconnected them from the switch as it might have chaffed and still be shorting out to earth, or cracked insulators under the coil mount ?

 

Brian

 

 

[RKW]

The coils are basically an auto-transformer and some have a diode across the primary so that they will only provide spark when the flywheel magnets pass in one direction only. Is it possible that one of your coils is facing the wrong way?

 

 

[JabSP6]

First thing to do is to check to see if the coil is producing spark.

 

Disregard the Distributors all together.

 

Pull both the coil leads out of the distributors and secure them to the motor so that there is a gap from the lead end to the earth on the motor of about 5 mm. Standing well clear of the prop turn the ignition on, Both Mag switches on and press the starter button.

 

As the motor winds over you should see spark at both coil leads. If not Disconnect the earth wires to the coils as Brian suggested to be sure you don't have a short in this earth wire.. Test for spark again. If you now have spark, replace your earth leads to the mag switches.

 

Still no spark then you need to check your coil gap to the flywheel. Should be around 10 thou. If you still have no spark replace your coil.

 

Make sure you refit fibre washers between the coil and the coil mount. This helps reduce the temp of the coils.

 

From what you say you have swapped the coil from left to right at the spider and only one coil works. I am a bit unclear from your description if the good coil worked in the both positions or if both coils worked in the one position. If both coils only give spark from one position it has to be a short to ground in the wire going to your mag switch of the bad position Remove the earth wire completely and give it a very good inspection.

 

If one coil only fires but in both positions i would replace the bad coil.

 

Keep it simple. Forget about the distributors. In this situation they only distribute the spark to each cylinder.

 

The spark is generated from the magnets in the flywheel passing closely to the coils (10 thou) as long as the starter motor is winding the motor over fast enough and the earth leads are not earthed. Must be a minimum of 300 rpm.

 

Make sure you keep everyone clear of the spinning prop while in test mode and be sure to remove the keys from the ignition each time you work on the motor just in case.

 

The only other thing to check is that you have both the distributors fitted in the correct position for your timing and you have the leads on the correct plugs. sound simple but i have seen them fitted incorrectly.

 

One way to check if you inlet manifold and tubes are leaking is to pressurise the carby by removing the supply tube and blowing in the carby with something like a vacuum cleaner on reverse cycle and spray soapy water on the manifold and pipes.

 

I have never tried it but apparantly it works.

 

Let me know how you get on.

 

Safe Flying

 

JabSP6

 

 

[hendonguy]

The coils are basically an auto-transformer and some have a diode across the primary so that they will only provide spark when the flywheel magnets pass in one direction only. Is it possible that one of your coils is facing the wrong way?

yes i disconnected the wires at the coil

 

 

[brilin_air]

and both coils have the leads in the same direction as the engine turns?

 

 

[hendonguy]

First thing to do is to check to see if the coil is producing spark.Disregard the Distributors all together.

Pull both the coil leads out of the distributors and secure them to the motor so that there is a gap from the lead end to the earth on the motor of about 5 mm. Standing well clear of the prop turn the ignition on, Both Mag switches on and press the starter button.

 

As the motor winds over you should see spark at both coil leads. If not Disconnect the earth wires to the coils as Brian suggested to be sure you don't have a short in this earth wire.. Test for spark again. If you now have spark, replace your earth leads to the mag switches.

 

Still no spark then you need to check your coil gap to the flywheel. Should be around 10 thou. If you still have no spark replace your coil.

 

Make sure you refit fibre washers between the coil and the coil mount. This helps reduce the temp of the coils.

 

From what you say you have swapped the coil from left to right at the spider and only one coil works. I am a bit unclear from your description if the good coil worked in the both positions or if both coils worked in the one position. If both coils only give spark from one position it has to be a short to ground in the wire going to your mag switch of the bad position Remove the earth wire completely and give it a very good inspection.

 

If one coil only fires but in both positions i would replace the bad coil.

 

Keep it simple. Forget about the distributors. In this situation they only distribute the spark to each cylinder.

 

The spark is generated from the magnets in the flywheel passing closely to the coils (10 thou) as long as the starter motor is winding the motor over fast enough and the earth leads are not earthed. Must be a minimum of 300 rpm.

 

Make sure you keep everyone clear of the spinning prop while in test mode and be sure to remove the keys from the ignition each time you work on the motor just in case.

 

The only other thing to check is that you have both the distributors fitted in the correct position for your timing and you have the leads on the correct plugs. sound simple but i have seen them fitted incorrectly.

 

One way to check if you inlet manifold and tubes are leaking is to pressurise the carby by removing the supply tube and blowing in the carby with something like a vacuum cleaner on reverse cycle and spray soapy water on the manifold and pipes.

 

I have never tried it but apparantly it works.

 

Let me know how you get on.

 

Safe Flying

 

JabSP6

hi thanks what i mean is i took the right hand coil which worked and the engine run , and replaced the left coil with the working coil and set the air gap but even with a proven coil i still didnt get spark , i removed the ground wire from the coil still no spark , i will have a go at seeing if i have spark at the high tension lead thats a good idea ,

[hendonguy]

hi thanks what i mean is i took the right hand coil which worked and the engine run , and replaced the left coil with the working coil and set the air gap but even with a proven coil i still didnt get spark , i removed the ground wire from the coil still no spark , i will have a go at seeing if i have spark at the high tension lead thats a good idea ,

i also know that the timing is correct the engine runs on one mag , all be it on 3 cylinders , even if the timing wasnt correct or the motor wouldnt go at all

[brilin_air]

rotor button cracked?

 

 

[hendonguy]

rotor button cracked?

thanks but bought new ones and swapped them the one that came from the side with good spark didnt give me spark on the bad one

[brilin_air]

hi thanks what i mean is i took the right hand coil which worked and the engine run , and replaced the left coil with the working coil and set the air gap but even with a proven coil i still didnt get spark , i removed the ground wire from the coil still no spark , i will have a go at seeing if i have spark at the high tension lead thats a good idea ,

 

(sorry i can't do the quote thing)

 

was it still from the same side that didn't get spark or was it the opposite side that lost its spark

 

 

[JabSP6]

Hendonguy

 

To keep things clear i will number the coils. Right hand position is coil no 1 and it works. Left hand position is coil no 2 and it doesn't work.

 

What you have done so far is try the working coil no 1 in the Left hand position but it didn't give you spark at the plugs. Technically if it works on the RHS and you put it on the LHS with the correct gap and the earth wire disconnected from the coil then you should get spark from the lead of the coil.

 

What i would do next is try no 2 coil, that didn't work on the LHS, and fit it to the RHS. Again check for spark at the coil lead. Do not connect either lead to the distributor when winding over. Make sure you use a jumper battery so you don't drain your battery. Be very carefull around the PROP when testing. Location on the engine of the coils is irrelevant as long as you have the coil gaps set correctly on both. If you don't get spark from one of the coils doing this test then i would suggest you replace the coil.

 

If you do get spark when testing this way from both coils then you can start to narrow your search to the LH Distributor components.

 

Hope this helps

 

Safe Flying

 

JabSP6

 

 

[Derby]

Have you checked to see if the magnet is still magnatized or not as magnets can sometimes demagnatize, just a thought.

 

Rory

 

 

[Yenn]

Do you have the instruction and maintenance manual? If not you can probably see it on line.

 

It gives tests for the coil, usa a multimeter and check resistance frop the P lead connector to the iron core of the winding, should be 0.8 to 1.0 Ohms. by iron core I mean the laminated metal that you set to run close to the magnets. Check resistance between the HT lead and the iron core, it should be 5.9 to 7.1 K Ohms.

 

If there is a problem with a magnet it would mean both cooils would work half the time. There is a set way to locate the coils as RKS says. I once tried to get both HT leads pointing down and found one coil did not work, put one up and one down and all OK. Can't remember which is which.

 

Just in case you need a new coil, they are Honda Part No 30500-Zic-023, Honda code 8584260

 

 

[brilin_air]

Leads in the direction of rotation

 

 

[hendonguy]

yes the leads are in the correct way the engine runs on one mag , I checked the spark at the high tension leads on the coils , had nice spark on the left none on the right , i bought a new coil and fitted it to the right hand side still no spark , if the magnets didnt have enough magnetic what ever the other side wouldnt work the earth wire isnt connected so its not a faulty switch , I am thinking the only thing it can be is the steel part of the coil should be earthed and for some reason its not im thinking of running an earth from left hand side coil to the right as the left works and thats the problem this should be a temporary repair or at least a test , anybody got any other ideas ?

 

 

[Louis Moore]

Thats a perplexing problem, you need to borrow my massive hammer?

 

Could not be an issue with the magnets or pickups on the spinny bit at the rear of the engine? (From memory that's where the magnet pickups were?) Incorrect gap set for the one not working (10though I think from memory again, but those more knowledgeable will know for sure)

 

 

[hendonguy]

yes gap set as per jabiru instructions

 

 

[hendonguy]

actually tried all sorts of different gaps

 

 

[brilin_air]

Has it got the insulators under the non sparking coil?

 

 

[hendonguy]

Do you have the instruction and maintenance manual? If not you can probably see it on line.It gives tests for the coil, usa a multimeter and check resistance frop the P lead connector to the iron core of the winding, should be 0.8 to 1.0 Ohms. by iron core I mean the laminated metal that you set to run close to the magnets. Check resistance between the HT lead and the iron core, it should be 5.9 to 7.1 K Ohms.

If there is a problem with a magnet it would mean both cooils would work half the time. There is a set way to locate the coils as RKS says. I once tried to get both HT leads pointing down and found one coil did not work, put one up and one down and all OK. Can't remember which is which.

 

Just in case you need a new coil, they are Honda Part No 30500-Zic-023, Honda code 8584260

Thanks for that , i cant understand how i missed this , but the problem was that i had both leads facing down and the coils must be directional some how , turned the the right hand one the other way and i now have spark,

 

 

[hendonguy]

thank you for everbodys help , i alway thought when i find the problem it would be a silly thing , and it was