How often do you verify carb/timing settings?

bashr52

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Aug 2, 2009
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Getting ready to put my 1994 4.3L back into service for the season and wondering if I should do a timing/carb check to verify everything is till within spec. I did a full tune-up last fall during winterization (plugs, cap, rotor, wires, oil change, fuel/water seperator). I bought the boat back in late July last year, everything seemed to run fine and work ok last time out. How often are you guys checking/adjusting your engines? Once a year before begin put into service, during winterization, midway through the season, etc? Adjust on muffs or in the water?
 

alldodge

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I only check or adjust when the motor when I notice a change. Only adjusted the choke one time, and have never touched the timing since the Rinker was new
 

Scott Danforth

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when I build the motor, then when I tune the motor the first few times out. I do periodically check the timing advance (maybe once every few years) just to verify the curve is where I set it. as far as carb setting, once I set it, I kind of forget it
 

HT32BSX115

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Getting ready to put my 1994 4.3L back into service for the season and wondering if I should do a timing/carb check to verify everything is till within spec. I did a full tune-up last fall during winterization (plugs, cap, rotor, wires, oil change, fuel/water seperator). I bought the boat back in late July last year, everything seemed to run fine and work ok last time out. How often are you guys checking/adjusting your engines? Once a year before begin put into service, during winterization, midway through the season, etc? Adjust on muffs or in the water?

In my 87 Four Winns 211 Lib, I removed the OMG460 in 2006 and installed the Mercruiser 1997 7.4L/Bravo......I timed it, set the carb and haven't touched it since.
 

Brentathon

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On my 1991 5.7 Merc w/ Rochester Quadrajet......I haven't touched the timing or the carb in the 17 years that I've owned it, except for the one time when the motor was replaced in 2007.
 

hal2814

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Feb 22, 2006
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I check timing when I replace a timing-related component. I do spark plugs yearly so that's usually it. I've never seen a spark plug change throw off timing so bad I need to adjust it, but I'm in there anyway and it's only a few minutes so why not? Back when I had a points ignition I was checking timing and cleaning/adjusting the points at least twice per season.

As far as adjusting the carb? When I notice a problem, which isn't that often. I adjusted it last year only to find out it really just needed a rebuild. Did my timing then, too.
 

Starcraft5834

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only had timing re-set with i pulled points in favor of elec ignition set up.... you shouldnt have to mess with it unless you mess with rotor...
 

Oshkosh1

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Jun 8, 2009
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I'm with the others; unless you're still running points...both are "RonCo" components/specs. "Set it AND......FORGET it"! Even points can pretty much be ignored for a long, long time.

That is of course until you have an issue...
 

Bondo

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Ayuh,..... I've had my barge for over 20 years,.... It's on it's 2nd, or 3rd set of plugs, cap, 'n rotor,...

Timin' is set at that point,....

I fought the carb for a year or 2, rejettin' it from Merc's specs, 'n ain't touched it since,....

Fuel filters get changed annually, or at anytime it runs bad,... step #1 in my diagnostic sequence,...
 

JerryIrons

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May 27, 2010
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Getting ready to put my 1994 4.3L back into service for the season and wondering if I should do a timing/carb check to verify everything is till within spec. I did a full tune-up last fall during winterization (plugs, cap, rotor, wires, oil change, fuel/water seperator). I bought the boat back in late July last year, everything seemed to run fine and work ok last time out. How often are you guys checking/adjusting your engines? Once a year before begin put into service, during winterization, midway through the season, etc? Adjust on muffs or in the water?

I run my boat on lake erie, where you do not want to have engine trouble, so I check things every spring (timing/dwell), and whenever I change something that could influence the timing. (cap, rotor, points) I put new a new cap and rotor on it at minimum every 3 years, and try to changes the fuel filters every other year. Usually I get everything adjusted in the driveway on muffs, and the first time I take it out I'll check timing out on the water, but it's usually ok. The only thing I've had to adjust on the water is the base rpms in gear. My boat is a 1986, with points and a distributor. I have found that usually the engine will telegraph to me that it isn't running at 100%, an intermittent bog down on acceleration I tend to notice first. Last fall I had some harder than normal starting, swapped out my ignition parts (cap rotor), and everything fine again.

One thing you can do, is measure the dwell at idle. Those points will wear over time, changing the dwell, which changes your timing.

Don't worry, you are a boat owner. You'll find yourself having to check/verify things all the time even without volunteering for it! Have cash in hand when you do! :)
 

bashr52

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Aug 2, 2009
Messages
413
This is a 94 4.3L with the thunderbolt 4 ignition, so no real points to worry about. The boat is brand-new to me, so I'm thinking verifying the timing and carb settings won't be a bad idea. I noticed some black plugs when I changed them last fall so I'm not sure if that is just from the time the boat was sitting (stored for a year before it sold) or mis-adjustment. I bought it in late July, and noticed the more I used it at the end of the season before I had to winterize, the better it ran. May have just been some bad gas working its way out of the system.
 

boatman37

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May 14, 2015
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theoretically you only need to check this stuff when there is a change to one of the components. your timing is a mechanical setting. your static timing won't change unless you change it. if you suspect your ignition module or some other issue is going bad then you can verify your settings but if you have no reason to think anything is going bad then really no reason to check it. that being said, it only takes a few minutes to check.
carb settings may be a little different. if you set it for a 95* high humidity day at sea level and you go to 5000' elevation in 40* weather you may need to make some adjustments. all things being equal, unless you change fuels or something like that then you really shouldn't need to adjust the carb until the next rebuild
 
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