mrlentle

I ran my brand new motor one weekend for about 5 minutes (wind got up) then stored. I went to start the next calm weekend and had very weak spark and would not fire at all. Have tried fresh fuel (I did drain in between runnings) new plug(s) an extra earth lead off of the grey coil and have tried adjusting the source coil to various postions to no avail. I don't know how bright the spark was before these issues but compared to my G260RC in my truck its pretty pathetic. Have considered pulling the coil from the truck but don't really desire taking a running RC off the road to get another on the water! Any help appreciated.

Matty_c

try this get the coil and put some cereal box cardboard in between the flywheel (the bit with the magnet on it) and the coil and push the coil down on the cardboard which is touching the flywheel and do the screws up. i don't have a zen but it works on my lawn mover my minibike and my boat a cracker box still in the making. so it might work on your zen because they were originaly a komatsu whipper snipper motor if you dont believe me go to there web site http://www.zenoah.net/ and find out for yourself
any way keep us up to date on what you are doing.


Matty_C

lzvagias

i'm going tto step out on a limb here and say that theres probably nothing wrong with your spark. i can't speak for the car motor but my g260 has never thrown an impressive spark, especially compared to that of my homie. if you want to be sure just temporarily put the cars coil on the boat and see if it fixes it. i'm thinking you should probably look at the carb block mounting screws. check to see if they are too long and making contact with the head. if so its likely that its letting air in around the block. its not uncommon for a new zen to run great at fisrt then suddenly start having troubles from this. just curious, how did you add an extra earth lead?

OLD_SLOW and in the WAY

take an ohm meter and check the resistance in the plug it should be close to 3000 ohms

lzvagias

the motor master has spoken!

OLD_SLOW and in the WAY

Being a motor master is far better than being an apprentice baiter

lzvagias

you said master baiter!

lzvagias

Larry, does leaving fuel in the carb for extended periods (like a week or two at a time) shorten the life of the carb diaphrgm? i go through them a little to frequently and i'm thinking it my fault.

OLD_SLOW and in the WAY

its a good idea to run the engine out of fuel when puttin it up.. pull the fuel line off the carb start it up and let the engine idle till the fuel is gone and the engine stops. dont rev it up cuz it will run lean and could damage the cylinder

skoda450

Back to the spark problem, I found that the spark plug cap connection to the wire can be a problem. It is a bayonet skewer from the plug cap connector into the wire. Sometimes it doesn't go in the center of the wire and will cause the problem described.

mrlentle

Ok looks like I need to hunt down a multimeter. Will try to find one at work today. Izvagias I added an earth lead from the grey coil earth mount (top screw) to the block - i found it as an ignition tip around here somewhere! And thanks for the carb block screw ideas but they are all ok. Fastrat, how do I measure plug resistance? i.e where do I put the + and - leads of the meter? Also if someone (fastrat) could tell me where to check coil(s) resistance would be great also.

billriach

Hi,

Might seem like stating the obvious, but change the spark plug first. Cheap, only a couple of quid (sorry $)
If it doesn't fix it at least you have a spare which you will use at some point.

Regards

Bill

BBuster

Is the choke on? Check carb with a mirror.
How about that kill switch?? Pull the ground wire.

mrlentle

Boat is virgin - I haven't even fitted kill switch yet so thats all ok and I have tried new plug(s) aswell as the one from the truck that was a nice fat spark. Am waiting for multimeter at present then will update. Thanks for all input.

mrlentle

OK I've done my coil checks:
Source coil 176.3 ohms
Ignition coil earth to plug cap 2027 ohms
Ignition coil earth to ignition coil red lead 1.0 ohm
Ignition coil earth to plug electrode 2940 ohms

The basic readings (from the manual) seem pretty close, is 176.3 close enough to the 185 in the book for source coil? What about ign earth to red - manual says should be .1 ohm and I get 1 ohm. Could this be my issue? If so how do I resolve? I'm starting to consder a viking funeral....

tazmaniaboats

sometimes it.s easier to test an eletrical device by trial and error
remove the grey coil of the boat and try it on the truck [buggy] remember to touch the copper earth flat point to a secure metallic area
before doing so check the spark in the dark of the truck then compare it to the boat,s spark .
if i m not wrong the difference between the red source coil to flywheel must be 0.03inch [but on slow revs this does not mater as long as the flywheel does not touch the coil
see you
imp wash your boat with fresh water if used at sea and after each wash start it to be sure that you store it ok