No Fire on a 540's
 

I have tried everything I can think of. I have no fire to the distributor, I thought maybe it was a bad kill switch, but that checked out ok. I replaced the coil, the plugs etc., I even checked the air in the tires. Please help.:grinser010:

If it has MSD, the box will be junk.

Start with a 12 volt test light and see if you have power to the ignition module first.

Have you ever had any voltage issues with your boat? If you have an MSD and run the ignition on less than 12 volts you can screw the ignition up.

If you have MSD. Swap the box from your other motor. or borrow one. One day it will fire, next day its a new Anchor. That's how one of my boxes went.

I don't have an MSD box on either motor. I just have an MSD coil, that I just replaced, with no luck. The only thing I did electrically, was install a new breaker on the fuel gauge. I unplugged the breaker and still no fire. It first started out on one motor, no neither motor will start...

if you have an MSD and try to run it on ANY voltage , the chances are good it will fail.

Have you run a test lead on the positive side of the coil to see if you're getting power when the ignition is on? Also, while cranking put a test light on the negative coil wire and see if the light flickers.

Takes less than 5 minutes to verify this, then we can go from there.

Tell us al little more of what you have. EFI?, regular distributor and coil? or what?

Blower motors with carbs, msd coil, reg. ignition. Motors crank only. Nothing is unplugged. All breakers are in good shape and operating correctly.

i had the same problem with one motor shut down and would not start(no fire), long story short after spending 630.00 on new dist.and hours of trouble shooting come to find out it was the tach wire that was bad. the motor fired right up until you hooked the tach wire up and it shut right down. thanks to jetmech for all his help in finding the problem.

Blower motors with carbs, msd coil, reg. ignition. Motors crank only. Nothing is unplugged. All breakers are in good shape and operating correctly.

What is your reg. ignition? Need 12vts at coil.

Is there a control module somewhere? In the distributor or a separate unit? There a number of different systems out there. Until we have a better idea as to what you have we are going to have a hard time helping you.

A couple of pictures might help

Had a distributor sensor go out on an HP500 a few weeks ago. Motor would just crank and crank and no spark. It was the old style with the studs on the sensor and when I pulled the distributor to prime the engine the studs loosened. These were HP500's with Thunderbolt ignition.

Small update:

I have used a test light on the coil, i have fire at the positive and the negative side of the coil, but still no fire at the plugs. Any suggestions?

What is the shape of the dist. cap and rotor?

did you pull the tach wire off? check my last post, we had the same and it was the tach.

dist. sensor ....Its under the rotor in the dist. These go bad all the time in the merc thunderboat 4 ing. system..

Yep, distributor sensor if T/bolt IV. I have a couple of distributors and am local if you need help.

I would appriciate your help.
Joe 301-904-9993

Fandago
 

Please get in touch with me

It's odd that both of them now won't fire. Were you parts swapping between motors? If so what was the last part you swapped over? Here is a pic of the old style distributor sensor, the new one style has molded in wires, and should come with a 'kit' to adapt if you have the stud style. Again this was on an HP500, pretty simple ingnition system.

I have the new style system in the distributor now, the only parts that were swaped were the ignition modules. I checked the coil and found that I have good fire at the positive and negative sides of the coil. when I put the test light in the center coil wire it shined very dim.

What is some more background on the issue? Did it just up and decide not to start one day? Batteries holding a good charge still? If you pull the coil plug off the coil, does it cross arc from the center post? Or if you have a helper you could hold the coil wire off the distributor some and see if it will arc across. Just use some insulated channel locks to hold the coil wire, it will give you a good shock. But if you aren't getting spark there, then work backwards, which it sounds like you already are.

Pictures of your setup definitely would help.

Wouldn't be the first time we chased ignition problems when we didn't have enough fuel in the boat/car/etc. LOL.

Dumb suggestion. Check the kill switches

Billy, thats the first thing I did check, however, thats exactly how its acting.:mad:

You probably have checked this but I will throw it out there make sure the main harness plug on the engine is pushed on all the way and I put a hose clamp around it if there's not one now. You can use a grounded test light to check for spark at the coil center tower with the coil wire removed have someone crank it over and hold the test light a 1/4 inch from the metal connector in the coil if there is spark you may want to ohm the coil wire and also check the rotor for a hole burned through the top of it allowing the spark to go to ground.

another thing that I have seen happen on more than one occasion. sounds like with what engines you describe, you most likely have a billet camshaft(roller cam). It is possible that you have eaten up a dist. gear due to wear on a bronze gear, or you were running a steel gear that is incompatible. Make sure the rotor feels "tight" when you wiggle it. then observe it while you are cranking it over to make sure it is spinning.