PDA

View Full Version : seems like the coil right?


Scot
05-16-2013, 01:37 AM
I recently got my boat back on the water after a pre-season tranny rebuild. Seems to be broken in and running great when suddenly it begins starting really hard when cold. Just replaced plugs, wires, rotor, cap, points, and set timing last season with only a few hours on it. Didn't rebuild the carb, so even though I didnt suspect it as the culprit, I rebuilt it and hoped that would solve it.

Installed my rebuilt Holley and tried to fire up. Still not wanting to start cold. In the process my starter burned up (No I wasn't cranking it for minutes at a time). Ordered a new gear reduction starter and ran the wires from the old solenoid to it. Nice clean connections.

Now I have a handful of symptoms and differential diagnoses. Starter is good. However, it only cranks about 60% of the time from the ignition switch. It cranks 100% of the time if I jump the solenoid. I am losing voltage somewhere in the ignition circuit.

Also, even when it cranks, it will not start. It is getting fuel (and flooding). When I pulled the plugs gas literally drained out of the rear cylinders. I blew the cylinders out after this. When I put a spark test light on one of the cylinders the light showed spark, but lit very dimly. To me this seems like either a bad coil or a bad connection in the dash.

I KNOW I have a bad connection somewhere in the ignition circuit from the starter symptoms. I have good power to the ignition switch and all the way to the coil when the key is on. These both COULD be related to a bad connection between the dash and motor, but seeing how I have good power to the coil no matter what and intermittent power to the starter circuit it seems like 2 separate issues- a bad connection for starting and not enough spark when cranking.

Will a bad coil still give a weak spark? Or are they all or nothing? My plan is to replace the coil and see if it will start, then trace the problem in the ignition circuit. I will probably replace the old glass fuse box while I am at it. Any thoughts? Both issues could be related but my testing indicates otherwise so far

thatsmrmastercraft
05-16-2013, 10:23 AM
The questionable power to the ignition may be your initial problem. I would do some careful checking on this with your voltmeter. I would clean all battery connections at this point...including the block ground. I would also confirm your points are at least gapped correctly and that they haven't burned. Did you set them with a dwell meter? Replacing the coil is not a bad thing to do here. While I'm not a parts thrower, I'm willing to bet your coil has been there for quite some time.

Scot
05-16-2013, 10:55 AM
The questionable power to the ignition may be your initial problem. I would do some careful checking on this with your voltmeter. I would clean all battery connections at this point...including the block ground. I would also confirm your points are at least gapped correctly and that they haven't burned. Did you set them with a dwell meter? Replacing the coil is not a bad thing to do here. While I'm not a parts thrower, I'm willing to bet your coil has been there for quite some time.


I have brand new cables with clean connections. I have been meaning to replace the old glass fuse box for a while, that will give me a good chance to trace the problem out too. Points were set with a feeler gauge. Like you said, coil woulnt hurt either. Not a parts thrower either but I hate trying to diagnose with old worn out stuff like my fuse block, would rather have a fresh start. Also if the points come out I think I will go breakerless.

Anything special about a "marine" coil? I was thinking one of the heavy duty Accels or MSDs would be fine

thatsmrmastercraft
05-16-2013, 11:23 AM
I have brand new cables with clean connections. I have been meaning to replace the old glass fuse box for a while, that will give me a good chance to trace the problem out too. Points were set with a feeler gauge. Like you said, coil woulnt hurt either. Not a parts thrower either but I hate trying to diagnose with old worn out stuff like my fuse block, would rather have a fresh start. Also if the points come out I think I will go breakerless.

Anything special about a "marine" coil? I was thinking one of the heavy duty Accels or MSDs would be fine

When I first got my boat, there wasn't a clean connection on it. I actually removed the fuse block and cleaned it up well enough that it is still working just fine. Is your fuse block upside down under the dash? Fun place to work. I also found some corrosion in the main wiring harness connections that also could be a source for your voltage drop. Dielectric grease on all these connections will help prevent any future problems. I don't think there is anything special about a replacement coil for a points ignition, though I just replaced my point with electronic ignition and and upgraded coil. Couldn't be happier with the outcome. I

Scot
05-16-2013, 11:55 PM
Okay, spark is eliminated. Put a new coil on today whether it was needed or not. Got it started. Lets ignore my intermittent cranking for now, thats easy to trace later.

Motor ran super rich, was dumping way too much fuel which confirms that this has been a fuel issue all along. Black smoke was pouring out the exhaust. Wouldn't idle and didnt want to start back up when it died out. Plugs might have fouled, but thats just a symptom.

Why might it be running so rich? What could I have done wrong with my rebuild? Any "check this first" ideas?

Traxx822
05-17-2013, 12:04 AM
Jets is where I would start. Did you replace the needles and seats etc. How deep did you go on this carb rebuild?

Sent from my HTC VLE_U using Tapatalk 2

thatsmrmastercraft
05-17-2013, 02:03 AM
Did you use a marine carb kit specific to your carb number?
When you rebuilt the carb, did you replace with a 2.5 power valve?
Do you have the idle mixture screws 1.5 turns out?
Since trying to get it running, did it backfire through the carb? If so, you may have blown the power valve. These older carbs aren't protected. Start it up again and screw the idle mixture screws all the way in. If it keeps running your power valve could be bad, your float is set to high, or you have a piece of debris not allowing the needle and seat to close.

JimN
05-17-2013, 06:17 AM
I recently got my boat back on the water after a pre-season tranny rebuild. Seems to be broken in and running great when suddenly it begins starting really hard when cold. Just replaced plugs, wires, rotor, cap, points, and set timing last season with only a few hours on it. Didn't rebuild the carb, so even though I didnt suspect it as the culprit, I rebuilt it and hoped that would solve it.

Installed my rebuilt Holley and tried to fire up. Still not wanting to start cold. In the process my starter burned up (No I wasn't cranking it for minutes at a time). Ordered a new gear reduction starter and ran the wires from the old solenoid to it. Nice clean connections.

Now I have a handful of symptoms and differential diagnoses. Starter is good. However, it only cranks about 60% of the time from the ignition switch. It cranks 100% of the time if I jump the solenoid. I am losing voltage somewhere in the ignition circuit.

Also, even when it cranks, it will not start. It is getting fuel (and flooding). When I pulled the plugs gas literally drained out of the rear cylinders. I blew the cylinders out after this. When I put a spark test light on one of the cylinders the light showed spark, but lit very dimly. To me this seems like either a bad coil or a bad connection in the dash.

I KNOW I have a bad connection somewhere in the ignition circuit from the starter symptoms. I have good power to the ignition switch and all the way to the coil when the key is on. These both COULD be related to a bad connection between the dash and motor, but seeing how I have good power to the coil no matter what and intermittent power to the starter circuit it seems like 2 separate issues- a bad connection for starting and not enough spark when cranking.

Will a bad coil still give a weak spark? Or are they all or nothing? My plan is to replace the coil and see if it will start, then trace the problem in the ignition circuit. I will probably replace the old glass fuse box while I am at it. Any thoughts? Both issues could be related but my testing indicates otherwise so far

Change the oil ASAP. The gas in the rear cylinders will have leaked past the rings and has diluted the oil and you don't want to run or crank it that way. Disconnect the fuel line from the fuel pump and use a different fuel source (like a gas can for an outboard motor- these can be pretty cheap and it's an invaluable tool for troubleshooting.

A bad coil can provide weak spark but you can also get a spark tester to verify this. Try the old coil wire to see if there's any change.

Pull the spark plugs and check the voltage at the ignition switch while you crank- this eases the load on the starter and prevents gas from being drawn into the cylinders but I would still recommend changing the oil first. If you see that the crank wire shows low voltage (below 10 volts with plugs in, somewhat more without), make sure all connections are clean and tight. Also, look at the engine for the large, round plug, where the main harness connects to the receptacle on the engine (it's under the cover near the breaker at the rear of th e engine). Make sure it's clean and fits well.

Did you check the battery cables and clamps? They may look clean and tight, but if they aren't, it won't run well. Check the ground cable at the rear of the engine, too. This is a common location for corrosion. Inspect the cables at the battery, too- if the acid fumes penetrate the jacket, the cable will be damaged- the cab;e will be a lot stiffer and won't bend as easily as the rest of it.

Scot
05-17-2013, 10:19 AM
Jets is where I would start. Did you replace the needles and seats etc. How deep did you go on this carb rebuild?

Sent from my HTC VLE_U using Tapatalk 2
stock jets, same ones that worked fine previously. New needle and seat and everything that comes in the rebuild kit

Scot
05-17-2013, 10:25 AM
Did you use a marine carb kit specific to your carb number?
When you rebuilt the carb, did you replace with a 2.5 power valve?
Do you have the idle mixture screws 1.5 turns out?
Since trying to get it running, did it backfire through the carb? If so, you may have blown the power valve. These older carbs aren't protected. Start it up again and screw the idle mixture screws all the way in. If it keeps running your power valve could be bad, your float is set to high, or you have a piece of debris not allowing the needle and seat to close.

New 2.5 power valve. Started with the idle screws 1.5 out, turned them in to .5 out and it still ran rich. I think my next step is to pull the primary bowl again and check the float, needle/seat, and power valve.

thatsmrmastercraft
05-17-2013, 10:32 AM
New 2.5 power valve. Started with the idle screws 1.5 out, turned them in to .5 out and it still ran rich. I think my next step is to pull the primary bowl again and check the float, needle/seat, and power valve.

Sounds like the correct direction to go. And as JimN said, better get that oil changed A.S.A.P.

Scot
05-18-2013, 12:51 AM
Pulled the carb apart again today. Verified that the needle and seat close off with the float parallel (could not blow through the inlet by mouth). Again used my mouth to ensure that the power valve closes under vacuum. What else can I do check without seeming like I have a weird carburator fetish?

Are there any check balls I could have missed along the way? Is there any way the accelerator pump circuit can draw excess fuel if something isnt right?

When I reinstalled it today and cranked it over it fired right away. Then the fuel started pouring in. I dont get it, it seems like it should work.

JimN
05-18-2013, 07:48 AM
Pulled the carb apart again today. Verified that the needle and seat close off with the float parallel (could not blow through the inlet by mouth). Again used my mouth to ensure that the power valve closes under vacuum. What else can I do check without seeming like I have a weird carburator fetish?

Are there any check balls I could have missed along the way? Is there any way the accelerator pump circuit can draw excess fuel if something isnt right?

When I reinstalled it today and cranked it over it fired right away. Then the fuel started pouring in. I dont get it, it seems like it should work.

Was the carb on the same angle when you checked the float as it is when mounted on the engine, rather than being level?

Scot
05-21-2013, 01:25 AM
I am hopefully getting the upper hand here. I hate working with multiple systems failing and (both fuel and electrical have definitely been issues here), especially when there are so many potential spots for failure. I also hate "throwing the book" at a vehicle when I havent pinpointed the specific problem.

That being said, I am trying to get a fresh start and fix some stuff thats been needing to be done for a while and hopefully come out running.

As for the carb, I pulled it apart again, set the floats to shut off just SLIGHTLY lower and in the process found a stupid mistake that may have been the cause of my excessive fuel. I put two gaskets on the power valve. Oops. It seems to be MUCH better altough it is still flooding. I think its just normal flooding from cranking with bad spark now rather than just dumping too much fuel.

To get my electrical system right I am working through the whole system. Tonight I replaced almost every terminal on the motor and made sure connections were clean. I installed a new Accel coil, ordered an Ignitor 2 module, new cap, and plugs. Removed and bypassed the resistor. Pulled the entire dash wiring down to replace the terminals and re-route the rats nest as cleanly as possible. Been meaning to do that anyway and I have a couple days till the new parts arrive.

At least if this doesnt get it running it will be easier to trace the problem having cleaned up the wiring. If it still ends up dumping too much fuel I am at a loss, I havent heard of any other problems in the carb that will cause it other than the bowl getting too much gas or power valve problems.

Scot
05-21-2013, 01:27 AM
Oh and the oil will be changed immediately when I confirm that it is not still drowning the cylinders with gas

thatsmrmastercraft
05-21-2013, 01:29 AM
Did you manually check the power valve while you had it in your hand?

Scot
05-21-2013, 01:33 AM
Also, no backfires since carb rebuild. Last time I pulled it apart I sucked on the power valve to ensure that the diaphragm closes the valve under vacuum. I picked up a power valve block to try diagnostically if needed, but I dont see how it will make a difference if the power valve works anyway.

Scot
05-22-2013, 03:56 AM
Did you manually check the power valve while you had it in your hand?

It was on the metering body. Sucked on the diaphragm end and it closed

Scot
06-06-2013, 11:52 PM
All is figured out and running well. I was frantically trying to get this thing running right by Memorial Day but finally gave up and came back to it after a nice weekend at the river without it. The problem with running so rich was the incorrect gasket between the metering body and main body. Some carbs have extra metal around the hole for the accel pump. Mine does not and needs gasket sealing it. I was dumping a ton of extra gas through this leak. Changed the oil and it was probably half gas. Got it running with this change, tuned with a vac gauge, set the timing and now runs like a champ.

I was also having some electrical issues and found another culprit, pretty much the last thing I checked but my alternator was dead. Dont know why I didnt check it sooner, but glad to have everything else fresh anyway.

So I brought the boat home for a simple carb rebuild and ended up with a new coil, electronic ignition (had points before), gear reduction starter (burned the old one up during this time), alternator, and plugs.

A strange thing happened during the process too. My amp gauge seemed to "burn out." No power through it (no power to dash or motor without it). No continuity between poles. I bypassed it to finish my tuning. Ordered a new one and went to take the old one out, but decided to plug it in first just to see. Worked just fine. Any ideas why? Im keeping the new one for now just in case.

Lastly, anybody have any experience with DB electrical? I was skeptical of their low prices but decided to try them for my alternator and starter. Less than $100 each for a marine gear reduction starter and marine 105 amp 1 wire alternator. Both working great so far, and worth a shot for saving several hundred dollars.

catamount
06-07-2013, 10:01 AM
Some carbs have extra metal around the hole for the accel pump. Mine does not and needs gasket sealing it. I was dumping a ton of extra gas through this leak.

Any chance you have a picture of the "extra metal" you're talking about here? I can't picture it.

Got it running with this change, tuned with a vac gauge, set the timing and now runs like a champ.

Where did you hook up your vac gauge? I've been meaning to tune with a vac gauge myself, but am unclear on where to get manifold vacuum on a marinized engine.

Scot
06-10-2013, 12:26 AM
Any chance you have a picture of the "extra metal" you're talking about here? I can't picture it.



Where did you hook up your vac gauge? I've been meaning to tune with a vac gauge myself, but am unclear on where to get manifold vacuum on a marinized engine.\

I dont have a picture of the extra metal, but I will post a pic of the 2 gaskets. Can't remember ever seeing it, but I've only torn into a handful of holleys and I am no carb guru. It must exist somewhere because I learned about it on the Holley forum and they woulnt make the first gasket I used if it didnt.

I hooked the vac gauge up to the vent tube on the spacer, where the PCV valve hooks to. Might not be as good as hooking straight to the manifold, but I figured that tuning to maximum vacuum is probably going to be about the same there.

Had the boat out on the water this weekend and it ran great! Since I did a lot at once I dont know if the carb rebuild or ignition upgrades made a bigger difference, but it spun 4800 RPM no problem, wouldnt do more than about 4500 before. Started every time, would idle all day, and charged like it was supposed to. I dont think my secondaries were working at all before considering how clogged the vacuum tube to it was. Glad to get another season out of this motor. My plan is to pick up another block and and start collecting the parts I want for a motor swap when the time comes.

Also, the amp gauge got power through it a few times intermittently. Changed it out and no more problems. Strange because I replaced all of the gauges last year. Maybe a surge got it from all of my cranking and poor running with a starter that was shorting and bad alternator? Keeping a bypass wire in the boat in case it happens again.

JimN
06-10-2013, 08:09 AM
\

I dont have a picture of the extra metal, but I will post a pic of the 2 gaskets. Can't remember ever seeing it, but I've only torn into a handful of holleys and I am no carb guru. It must exist somewhere because I learned about it on the Holley forum and they woulnt make the first gasket I used if it didnt.

I hooked the vac gauge up to the vent tube on the spacer, where the PCV valve hooks to. Might not be as good as hooking straight to the manifold, but I figured that tuning to maximum vacuum is probably going to be about the same there.

Had the boat out on the water this weekend and it ran great! Since I did a lot at once I dont know if the carb rebuild or ignition upgrades made a bigger difference, but it spun 4800 RPM no problem, wouldnt do more than about 4500 before. Started every time, would idle all day, and charged like it was supposed to. I dont think my secondaries were working at all before considering how clogged the vacuum tube to it was. Glad to get another season out of this motor. My plan is to pick up another block and and start collecting the parts I want for a motor swap when the time comes.

Also, the amp gauge got power through it a few times intermittently. Changed it out and no more problems. Strange because I replaced all of the gauges last year. Maybe a surge got it from all of my cranking and poor running with a starter that was shorting and bad alternator? Keeping a bypass wire in the boat in case it happens again.

Your ammeter worked sometimes and everything after the ignition switch still received current? An ammeter is wired in series on the battery lead, not parallel, like a voltmeter. That may be the problem- it's supposed to feed a load, not be the load.

Scot
07-16-2013, 01:02 AM
No, sorry for the confusion. When I say it worked intermittently I mean that when it was not working, nothing else worked. No power through it