3.0 mercruiser timing tab missing

jdcole

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Oct 10, 2016
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Hello everyone I recently purchased a 96 bayliner capri 1950 with a 3.0lx engine. I've been having a issue going from idle to full throttle. I've rebuilt the carb seems to have gotten better but still has some hesitation. I was going to check the timing and found the timing cover had been replaced with a automotive cover. Has anyone ran into this? Can I get a add on tab? Help please. Thanks
 
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achris

More fish than mountain goat
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May 19, 2004
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Merc don't do one (that I'm aware of) and none of the after markets appear to either. I think you'll find all covers for those engines do have a pointer on, but that one has either broken or rusted off.

You do have a couple of options.
1. Probably the least appealing is to replace the cover with a new one.
2. Get one of the SBC aftermarket pointers that will fit in place (or make your own) and bolt on with the side screws of the cover, then put a length of timing tape on the balancer.... That will require you accurately finding TDC of course. ;)

Chris........
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Welcome aboard.

the 3.0 has no automotive applications, the closest being its 2.5 sibling that was found in the 1962 and 1963 Chevy II

however as Chris pointed out, the stock tab most likely rusted off

us a dial indicator on the piston, locate TDC then make a pointer and use timing tape.

or pull the motor, pull the oil pan, pull the timing cover, replace, then reinstall everything.
 

jdcole

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I was told by the previous owner that the timing cover was a dorman 636506 this was a timing cover for a 2.5 Iron Horse GM Block. From what I was told. Thanks for the info
 
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Fishermark

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Oct 19, 2003
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I think you may have a typo. I did find a Dorman cover #635-506 which looks right... but couldn't guarantee it! Found that at Summitracing for $17.

RNB-635-506_ml.jpg
 

RaceCarRich

Petty Officer 1st Class
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May 31, 2015
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You can find TDC using a tool similar to a comp cams 4795. Just get the right one for your application. No disassembly needed.

Also, if you have an advance timing light, you shouldn't need the timing tape.
 

fishrdan

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Jan 25, 2008
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Here's what you're lookin for. Not cheap, but better than paying $80 for a used timing cover off Ebay with the timing tab. You want the 1:30 position tab, not the 11:00.

http://mrhotrod6.myshopify.com/prod...-adjustable-timing-pointer?variant=1142521973

It seems the timing tab cover you're looking for is strictly marine - or off early model GM 4cyl and straight 6 engines, 153, 181, 230, 250, hard to find 40 years later... If you have a wrecking yard with old vehicles, that may be a possibility for a cheap cover.
 

jdcole

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Anyone know where I can find a junk mercarb for parts or number 7,22, and 23 in the picture?
 

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Scott06

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Apr 20, 2014
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Would try mikes carb parts or (no joke) mountain man fuel systems 479-639-2022 he's on eBay under seller mountaintink.

Mountain man had the best price on electric choke elements for my mercrab.

22 &23 missing make it hard to idle.. alternatively and old Rochester 2 jet may have the same parts if you have a u pull it yard or somebody who collects old GM carbs
 

jdcole

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Oct 10, 2016
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Thanks for the info. I already tried mikes carbs no luck there. I'll try mountain man. Thanks again
 
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