Help! 1999 1900sr Engine and Electrical Problems

[mmwjr]

Coils can test good at ambient but when running they get hot and can be intermittent. This will cause a miss that may backfire.

[precool26]

Ok. I will get me a timing light probably tomorrow. Do I need a certain one? And as far as the tach/dewell, are you talking of a new gauge or something I plug into the engine when I set my timing?

[precool26]

Will this tach work: http://m.harborfreight.com/lcd-automotive-multimeter-with-tachometer-kit-95670.html

And I'm guessing I need the xenon advanced timing light?

[precool26]

Originally Posted by mmwjr

Coils can test good at ambient but when running they get hot and can be intermittent. This will cause a miss that may backfire.

Well, how would I test the coil then....accurately?

[Corfab]

Originally Posted by precool26

Well, how would I test the coil then....accurately?

I had a coil once that would get hot and quit. you could ice it down for a few minutes and it would continue to work again, until it overheated again.
in a perfect world, you could ohm the terminals to find an open or shorted coil. Doesn't always work though.

[mmwjr]

Originally Posted by precool26

Ok. I will get me a timing light probably tomorrow. Do I need a certain one? And as far as the tach/dewell, are you talking of a new gauge or something I plug into the engine when I set my timing?

Any timing light will do.

Separate tach/ dewell meter, they were used back in the day when engines had points. It will connect to the battery and coil using clips.

[mmwjr]

Originally Posted by precool26

Will this tach work: LCD Automotive Multimeter with Tachometer Kit

And I'm guessing I need the xenon advanced timing light?

That will work.

[mmwjr]

Originally Posted by Corfab

I had a coil once that would get hot and quit. you could ice it down for a few minutes and it would continue to work again, until it overheated again.
in a perfect world, you could ohm the terminals to find an open or shorted coil. Doesn't always work though.

Yes you can measure between the positive and negative terminals which should be a few ohms. Then measure between the positive terminal and high tension post, which has another value that you'll have to look up.

As said when they get hot they internally short so no way to test until it fails. A can of freeze mist can be used to cool it down to see if that fixes it.

[mmwjr]

Being a 1999 the engine is equipped with a knock sensor so if there is an issuer with the fuel causing a knock the module will retard timing.

Therefore you may want to try running on an external gas can as I mentioned before.

[precool26]

Is there was a way to bypass a knock sensor to test if that's causing the retard?

[mmwjr]

Originally Posted by precool26

Is there was a way to bypass a knock sensor to test if that's causing the retard?

Not sure. maybe unscrew it from the block and plug the hole. you'll then need to ground the outer case of it.

[mmwjr]

Get the Mercruiser manual from the Documents tab of this site its #24, there is a section that describes how to test the knock sensor. This manual has looks of info and troubleshooting guides.

[precool26]

Ok guys, quick question.. I'm looking at my distributor cap and it has two orders. One says standard, the other "rev". Which order do they go in? Standard reads 12756348. Rev reads 18436572. Something I read on another forum last night said the latter one. If that's so, they all in the wrong spot right now..

[precool26]

And why would taking some of my plugs off my cap not make a noticeable difference like some others. I here them sparking. Erratically though, not synchronized at all. Very erratic

[mmwjr]

Originally Posted by precool26

Ok guys, quick question.. I'm looking at my distributor cap and it has two orders. One says standard, the other "rev". Which order do they go in? Standard reads 12756348. Rev reads 18436572. Something I read on another forum last night said the latter one. If that's so, they all in the wrong spot right now..

It's a standard rotation, rev is for a twin application were one engine runs in reverse. These days most twins are both standard and the transmission does the reversing.

[mmwjr]

Originally Posted by precool26

And why would taking some of my plugs off my cap not make a noticeable difference like some others. I here them sparking. Erratically though, not synchronized at all. Very erratic

No science here, use a gap tool to test spark they are cheap at an auto parts store.

[precool26]

This Mercruiser manual is a treasure trove of info! Thanks Mike. I Have a question. The ignition coil in this manual looks nothing like the one I have on my engine. I followed the center wire off my cap to the portside aft of my engine. It was a black cyclinder with two wires running to it (Grey, and another color) and the high tension lead itself. When I unplugged the lead, it has more of a hole in it than than a tower to connect to. My lead has a prong inside the boot that fits down into the coil. Am I seeing this correctly, or could I possibly have the wrong coil? I am going to try everything you guys have mentioned this weekend when I have time off of work. Right now Im just tinkering and worrying myself!!!

[mmwjr]

I think what you described sounds correct but a few pictures would help.

The coil is about the size of a soda can but smaller in diameter. The gray wire is on the negative terminal and goes to the tach. The positive terminal wire goes to the ignition sensor in the distributor.