Determining Position of #1 / Correct Firing Order
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=41408
Printed Date: October-06-2024 at 10:16pm
Topic: Determining Position of #1 / Correct Firing Order
Posted By: CORYM
Subject: Determining Position of #1 / Correct Firing Order
Date Posted: July-03-2017 at 2:36pm
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Hi Everyone, in need of some help relating to the spark plugs. When replacing the cap/rotor I crossed some spark plug wires. I am having a hard time determining the exact position of the #1. I have found the correct firing order, but want to make sure I am starting at the right place on the cap. I have the later 351- 1-8-4-5-6-2-7-3 Firing order-  Example I was trying to follow-  My engine-      |
Replies:
Posted By: Dreaming
Date Posted: July-03-2017 at 2:41pm
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Find the # 1 cylinder, and then make sure that it is at TDC on the compression stroke. (Remove the spark plugs (all of them) use a breaker bar on the crank pulley up front to turn the engine in the correct direction and hold your finger over the spark plug hole of # 1) When you feel the pressure building on # 1, it is on the compression stroke. Line up the TDC mark on the pulley with the timing mark on the engine block. Then pop your distributor cap off. The distributor rotor will be pointing to the terminal where # 1's wire should go. Start there and work the firing order around the distributor cap until you have all 8 attached in the proper order around the cap. Make sure you note the direction of the distributors rotation, I am pretty sure it is counter-clockwise, but it has been a while since I looked at mine. your diagram above agrees with my memory, but it doesn't hurt to check it . the reason you are probably confused is that the position of the distributor/rotor when it installed is not "set". you can drop the distributor in in any position around the clock. Most people set # 1 to point to the # 1 cylinder, but this may not be the case for your particular set up. You have to verify the #1 cylinder position by visual cues as described above. once you find #1, you could mark the cap so that you don't loose it's position for next time. |
Posted By: Dreaming
Date Posted: July-03-2017 at 2:52pm
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PS - that doesn't look like the marine fuel bowls that I have seen in the past. Do you have a different carb on your engine? Maybe a 4110? not necessarily a bad thing, just different than I am used to seeing. |
Posted By: KENO
Date Posted: July-03-2017 at 4:39pm
The early Holley marine carburetors had adjustable floats like the ones pictured with the external adjusting screw. They got phased out in the late 70's probably more as a cost saving thing It was at about the same time that J tubes showed up on marine Holley's. I doubt the USCG has a problem with the adjustable floats since a Quick Fuel carb has them. Those bowls have the more universal fuel inlet location as compared to the Ford marine versions. It could be a Chevy version of a 4160 marine carb with that fuel inlet location.or..............it could be an automotive carb. It looks like the original fuel line with a short piece added to get to the new inlet location. A picture showing the list number on the air horn would tell  It's not a 4110, they don't have removable float bowls. The whole top comes off the carburetor to get at the bowl internals |
Dreaming wrote:Posted By: KENO
Date Posted: July-03-2017 at 4:42pm
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Follow Dreaming's description of finding #1 and wire installation and you'll be fine. Your 351W distributor always goes CCW no matter which way the engine rotates |
Posted By: Dreaming
Date Posted: July-03-2017 at 7:41pm
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externally adjustable floats would be cool... if I ever needed to replace my carb I would sure check out the QF because of that design feature. I too noticed the fuel line extension and the different fuel inlet location from my carbs, thus the question. Thanks for the education Ken, I always like seeing/hearing/learning from you more experienced guys. |
Posted By: KENO
Date Posted: July-03-2017 at 10:21pm
That's just your nice way of saying "you old farts". You can buy the parts from Holley to do the bowl swaps. All the parts probably add up to over a hundred dollars though. I've bought a parts carb with those bowls on Ebay pretty dirt cheap and cleaned and swapped bowls before. |
Posted By: Riley
Date Posted: July-03-2017 at 11:13pm
| Holley make a 4150 marine carb that has adjustable floats and a sight window. They do cost more than the 4160 that PCM used. Malibus had them on their Indmar carb engines. |
Posted By: Dreaming
Date Posted: July-05-2017 at 2:16pm
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Riley and KENO that's pretty cool. maybe my "cheap" self will look for a set of those bowls instead of a whole carb if I need to redo them. Also, another cool difference that I learned about between 4150/4160 is that the 4150 has adjustable secondary jets instead of a metering block. Must have been the a higher end offering |
Posted By: CORYM
Date Posted: July-06-2017 at 1:32am
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Thank you for the advise, With the busy schedule / limited shade, I hope to dive into it Sunday. The boat came this way. It is a 1986, I know the previous owner had the heads off for a rebuild, I am not sure if carb would have been changed around at that time. I am not a carburetor guy at all! |