Merc 4.3 v6 distributor cap and cilinder connections

[Bondo]

Never assume the tower on the dizzy is in a specific location. The tower the rotor is pointing to when the motor is at TDC is number 1

Ayuh,..... Exactly,.....

If changin' the cap, 'n rotor don't fix yer problem, pull the fuel filter, 'n examine it's contents for anything but clean fresh gasoline,....

 

[wake800]

Never assume the tower on the dizzy is in a specific location. The tower the rotor is pointing to when the motor is at TDC is number 1

Ive read other forums explaining how to do this for the TDC part, i will check. I assumed the original dizzy cap had the labeling correct, meaning the number on the tower meant the cylinder it should go to having both right or left handed numbers. Thanks for the heads up!

And for the first time i think i understand your first comment on " tower one is going to cyl 3". If we take this way if numbering going counter clockwise it would be connected correctly. So if tower one is really 3, then counterclockwise the next number would be 4, then 5.. consecutively. All connections line up .

I know you talked about the TDP, is it normal that the numbers on the oem dizzy cap dont match then??

 

[wake800]

Ayuh,..... Exactly,.....

If changin' the cap, 'n rotor don't fix yer problem, pull the fuel filter, 'n examine it's contents for anything but clean fresh gasoline,....

Thanks will do, ive read the forum on all the reasons it doesn't reach full WOT. So will be changing the filter even if its clean, i checked the carb fuel filter and it looks fine, so will ve doing a couple of things at a time

 

[Scott Danforth]

I assumed the original dizzy cap had the labeling correct,

possibly. however do not count on it.

find TDC on the motor, look at the rotor location. that is tower 1

 

[Bt Doctur]

If no backyard mech has hacked it up follow the diag in post 7,. If someone has screwed with the dist, remove number 1 plug and the dist cap.
crank motor listening for a rush of air. Your coming up on number 1 compression. Quickly tap the starter to bring the timing mark to zero. Where the rotor points to is number one Then in a clockwise rotation 1,6,5,4,3,2

 

[nola mike]

Looking at your original setup...you've got the cylinders numbered wrong, but connected correctly. So your #5 on the dizzy is actually the #1 cylinder, #4 is #6 cylinder, etc. This will run fine unless you try to time it using your labeled #1 plug wire, which is actually the #3 cylinder. You'd have to time it using the wire going to cylinder #1 (marked #5 on your dizzy). The "fix" is to remove the dizzy and reposition so that at TDC the rotor is pointing at the #1 mark on the dizzy (instead of #5). OR remove the cap, rotate it 120' CW so the number 1 mark on the cap is where #5 is now (if the cap fits that way). Anyway, it will be perfectly happy as long as you realize what's going on...but it will be confusing.

 

[poconojoe]

Take anything the previous owner said or claimed he has done with a grain of salt.
There's no guarantee it was maintained correctly.

 

[HalfWolf]

Hey guys, I got a used Regal 2005 boat with a MerCruiser Chevy Vortec 4.3 v6. Im checking my t's because it is only getting 3600rpms and max 33 mphs. With a three blade 19 pitch and 4 blade 17 pitch both around 14 inches. Im pretty sure i know it can get more so I've been checking things on the boat and the forum.

Two questions about the distributor cap:
One is if in the pictures i have attached does it look like it needs to be changed?

2nd - is it connected correctly, the motor turns fine and works but according to the timings and what cylinder should be connected to what point-needle on the dist cap they would ve incorrect. Im not sure if i should move the wire plugs to how they are supposed to be. The diagram below is how it is connected as of now and the bottom part is the front of the boat and the distributor cap is how it looks from above on the motor installed exactly.
Moreover you can also read about Firing Order for 351 Windsor here https://nerdycar.com/firing-order-for-351-windsor/

The correct firing order and cylinder-to-distributor connection are crucial for optimal engine performance. If the wires aren't connected in the right order, it can lead to misfires and lower RPMs. The diagram you've shared is quite useful in showing how the wires are currently connected. However, I'd recommend double-checking the engine's manual or a reliable online resource to ensure that the connections match the recommended firing order for your MerCruiser Vortec 4.3 V6 engine.
Making sure the wires are properly routed and connected according to the correct firing order could potentially help you get more RPMs and better speed. If you're unsure about making changes yourself, consider reaching out to a marine mechanic or someone experienced with boat engines to assist you. Good luck, and I hope you can get your boat running at its best!

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