Firing order diagram, correct or incorrect??

[brokemerc]

1995 Bayliner 1854 capri 3.0.. Quick question about the firing order. I believe the manual says the order is 1-3-4-2 and in the mercruiser manual it shows a picture of the engine with the numbers 1-2-3-4 with 1 being forward and next to that is a round distributor with lines going from the distributor to the cylinders. My question is how accurate is this picture?? Is the most forward inbd plug wire on the cap really #1??? I know I should find #1 tdc and figure it out myself but hopefully mercruiser would put an accurate picture in their maintenance manual. If so I think I figured out why my boat didn't run the other day... (2 out of 4 correct aint that bad..)

 

[Chris1956]

Re: Firing order diagram, correct or incorrect??

The firing order is different than the numbers of the cylinders. The numbers of the cylinders on an inline is usually 1-2-3-4. To set the firing order you arrange the plug wires on the cap in the correct order so as the rotor turns it hits the plug wires in the correct order. The dist. caps sometimes have the firing order molded in.

The best way to learn is to pull the spark plugs, turn the engine using the starter or a big wrench until the TDC indicator and timing mark on the main pulley aline. This is top dead center on number 1 cylinder. Stick a screwdriver into the plug holes, and verify the frontmost cylinder is #1.

 

[Bondo]

Re: Firing order diagram, correct or incorrect??

I know I should find #1 tdc and figure it out myself

Ayuh,...... That is Correct......
And that's TDC on the Compression stroke, as TDC can also be the Exhaust stroke.....

My question is how accurate is this picture?? Is the most forward inbd plug wire on the cap really #1???

Ayuh,....... Usually, but not Always.......

The Distributer can be pulled out,+ rotated so that Any 1 of the 4 terminals could be the #1 terminal......

 

[brokemerc]

Re: Firing order diagram, correct or incorrect??

Yes I know, the order is I believe 1-3-4-2 and the distributor rotates clockwise. So like I mentioned the manual has a picture of the block and the four cylinders and also has a round circle which is suppose to be the distributor. The most forward inbd distributor wire goes to #1,, and then clockwise from there 3-4-2.. My question is weather or not this diagram is correct,, it would save me a bunch of time if it is plus would tell me that either 2 or 3 of my wires were on the wrong plugs... (i wish I could clip and paste that picture) Breaker Point Ignition

 

[Bondo]

Re: Firing order diagram, correct or incorrect??

My question is weather or not this diagram is correct,,

I Just Told You,........ MAYBE..........

If the distributer was Installed with the Rotor pointing to THAT Terminal,......
Then Yes......

If the distributer was installed with the rotor pointing at a Different terminal,.....
Then NO.......

I Know the Picture,........
But it depends on WHERE the rotor was pointing when the distributer was installed.......
I wasn't there when somebody stabbed the distributer,.....
Who Knows whether it was stabbed in THAT position........

 

[brokemerc]

Re: Firing order diagram, correct or incorrect??

Sorry, i was trying to paste the picture and didn't see your response. Thanks.. I'll pull the plugs and check tdc just to be sure..

 

[JCF350]

Re: Firing order diagram, correct or incorrect??

Once TDC (compression stroke) is located the rotor should point towards the #1 cyl. if not, remove and re-index the distributor so that it does. This is something that GM generally does and why it is shown that way in the manual.

It really don't make any difference where #1 is, but you run into folks who don't know no better claim that the firing order is wrong, plus I index it correctly just to be professional about it.

 

[brokemerc]

Re: Firing order diagram, correct or incorrect??

Pulled all plugs and cap,, TDC ended up being 90 degrees clockwise from what the manual says, so I actually did not have a single plug wire on the correct plug.. I'm really surprised that it even fired up and ran even if it was only for a few seconds. Put it all back together,, tomorrow will be the test (i was too scared and feared disapointment). Didn't re index the distributor,, maybe after I see if it'll run..

 

[Chris1956]

Re: Firing order diagram, correct or incorrect??

Hey, That happens. One fall I needed to replace the trigger in my '88 Alpha 1. In order to do this, I needed to remove the rotor shaft, to have access to the trigger. When I put the dist. body and shaft back into the block and timed it, it wouldn't even pop.

After cranking with a timing light showing exact timing, and no start, I went in to watch a football game(Jets and Raiders). By the second qtr, I figured out I was 180 degrees off in timing.

I had not installed a distributor into an engine in 30 years, so I forgave this lapse....

 

[Fishermark]

Re: Firing order diagram, correct or incorrect??

Not to add confusion to the mix... but you do understand that it doesn't matter where the number 1 on the distributor is -right? In other words, as long as, while at TDC on the compression stroke, it points to the terminal on the cap that has a spark plug cable on it that goes to number 1, then that's all that's necessary. The rest of the cables go on clockwise from there. It doesn't matter if that terminal is pointed to the front or ninety degrees off - any terminal will work for a starting point. I'm not sure if I explained myself or not - and maybe you already know that... but I thought I would at least try to make things clearer.

 

[Caveman Charlie]

Re: Firing order diagram, correct or incorrect??

I just put now wires on my Mercruiser 140. The picture in the manual was wrong according to how my engine was times. Yes, the 1342 part was correct but, my cap has number one marked and that was one point on the cap away from the block. So, instead of being next to the block like your saying and the pictures in my book also said the number one wires is one spot away from the block on the front of the cap. If you get what I mean. That's how it was wired and it ran last summer so I put it back that way. I did not pull the distributor and have no idea if anyone ever has.