Vacuum advance for 140?

[SSTKO81]

I recently found myself in need of a new distributor and found a part number cross reference that directed me to one with a vacuum advance. Now mine (1981) doesn’t have vacuum advance but I guess I could see the benefit of adding it. Has this been tried? Any thoughts on why it would be a bad idea? -I’m just curious at this point

 

[Scott06]

Never seen a marine distributor with vacuum advance must be an automotive distributor. Marine engines don’t run where vacuum advance would be advantageous like part throttle cruise, marine engines are under load at all times

 

[kenny nunez]

What part of your distributor is worn out? The flyweights or is the shaft too loose?

 

[thumpar]

It's not a marine distributor if it has vacuum advance.

 

[kenny nunez]

If the centrifugal advance parts are in good condition take the shaft out and bring it to a machine shop. Have a new bushing installed in the top and a second bushing installed in the bottom by just boring out the housing and fitting a bushing. There never was a lower bushing in the distributor, there is a bushing just above the oil pump in the block that is worn out.
Anyone with a small lathe can do this.

 

[SSTKO81]

Bushing are fine, problem with mine is that the gear is damaged. There’s a chunk missing from then end of one of the teeth

 

[achris]

The end should be fine. As the cam gear is more circular, the end of the distributor gear shouldn't ever be meshed anyway. How much is missing?

Chris......

 

[SSTKO81]

About half of one tooth

 

[SSTKO81]

I guess really I just need a new gear

 

[Rick Stephens]

With a fairly quick search, the only two I found must of been gold plated. Example here. However, it does tell you what you are looking for. Gotta be a pulled motor somewhere you can get a disty out of if you can't find just the gear.

 

[kenny nunez]

Just to be sure, take a close look at the cam. It Is very possible that something went through the oil pump and the cam is also damaged.

 

[SSTKO81]

Just to be sure, take a close look at the cam. It Is very possible that something went through the oil pump and the cam is also damaged.

That’s how I arrived where I am... had to pull the cam to change the fiber gear and that’s when I found the dizzy gear. Cam looks great tho, like really great.

 

[achris]

That’s how I arrived where I am... had to pull the cam to change the fiber gear and that’s when I found the dizzy gear. Cam looks great tho, like really great.

... Fibre gear!!!! That is NOT factory standard. ALL Mercruiser in-line GM engines had a steel crank timing gear and an ALUMINIUM cam gear. If it has fibre, then someone has messed with it, or the engine is not original... DO NOT put a new fibre gear on, get the proper set from Merc.

Chris.....

 

[SSTKO81]

... Fibre gear!!!! That is NOT factory standard. ALL Mercruiser in-line GM engines had a steel crank timing gear and an ALUMINIUM cam gear. If it has fibre, then someone has messed with it, or the engine is not original... DO NOT put a new fibre gear on, get the proper set from Merc.

Chris.....

Too late for all that. It’s had a fiber gear in in for 20 years and that’s what went back in. If it lasts another 20 years and fails, then I’ll deal with it then. -that distributor gear replacement is pricey enough! Does Sierra make an alternate?

 

[Rick Stephens]

Too late for all that. It’s had a fiber gear in in for 20 years and that’s what went back in. If it lasts another 20 years and fails, then I’ll deal with it then. -that distributor gear replacement is pricey enough! Does Sierra make an alternate?

You now have the right part number to search with.

 

[Scott Danforth]

... Fibre gear!!!! That is NOT factory standard. ALL Mercruiser in-line GM engines had a steel crank timing gear and an ALUMINIUM cam gear. If it has fibre, then someone has messed with it, or the engine is not original... DO NOT put a new fibre gear on, get the proper set from Merc.

Chris.....

Chris, the 2.5 / 3.0 and the inline 6 originally had fiber gears on the cam from GM. Aluminum didnt come out until later

 

[kenny nunez]

I asked the Mercruiser rep years ago why the marine in line engines had fiber cam gears. He said it made the engines quiter since it was so close to the boater. And as the poster said it was 20 years old.
Cheverolet used fiber cam gears in the passenger cars up to around 1962.

 

[SSTKO81]

I asked the Mercruiser rep years ago why the marine in line engines had fiber cam gears. He said it made the engines quiter since it was so close to the boater. And as the poster said it was 20 years old.
Cheverolet used fiber cam gears in the passenger cars up to around 1962.

Well I feel better about this....

back to the dizzy gear

 

[fishrdan]

I wouldn't worry about the fiber cam gear. I rebuilt my 73' 140HP about 10 years ago, the original fiber cam gear was in good condition, so I went back fiber during the rebuilt. I didn't want to chance the aluminum gear being noisy.

back to the dizzy gear

Did you check the cam distributor drive gear to make sure it's not messed up, due to the broken tooth. Also, are the bushings in the distributor good, shaft sloppy. Depending on how much you want to spend, Delco makes a "Voyager" complete ignition system for your engine, $300+. I have seen Mallory distributors pop up on Ebay that will fit a Mercruiser GM 4cyl

For the gear, Check you PM's

 

[Grub54891]

My 140 had the fiber fear, 1985. It had some chips missing when I refreshed the gaskets replaced with metal gears.
Now back to your dizzy gear, yeah absolutely replace it.