Merc. 3.0 points too close?

[dswi]

Fixed a starter issue the other day. When I cranked it up in the yard with the rebuilt starter noticed that it cranked easier and faster than it ever has!! Great!!
Adjusted the points to .022 as per air filter cover says...Seemed to starter harder with the adjustment. The points were originally less than .022...Is there a possible reason that someone had the points closer than they were supposed to be? What would this do to running and such. I don't have a dwell gauge but do have feeler gauges.

 

[Bondo]

Re: Merc. 3.0 points too close?

Fixed a starter issue the other day. When I cranked it up in the yard with the rebuilt starter noticed that it cranked easier and faster than it ever has!! Great!!
Adjusted the points to .022 as per air filter cover says...Seemed to starter harder with the adjustment. The points were originally less than .022...Is there a possible reason that someone had the points closer than they were supposed to be? What would this do to running and such. I don't have a dwell gauge but do have feeler gauges.

Ayuh,.... Changin' the point gap, changes the timing,...

Set the points, then the timing....

 

[Oshkosh1]

Re: Merc. 3.0 points too close?

And remember...as the gap decreases(from the wear block, well...wearing)...the dwell angle (the number of degrees through which the distributor cam rotates while the breaker points are closed)increases.

I had an "old timer"...one of the local ancient marine techs here tell me to set the dwell a little low, like 2-3 degrees(not sure exactly how that translates to gap measurement...but it's not much) on new points as the wear block will initially wear quickly to fit the distruibutor lobe, then will errode a little slower once it's worn to fit. I did this, on my motor set the dwell @ 26. After just a few hours of running I checked it again and it was 28 and hasn't moved yet. Use a little grease on the wear block so it's self lubing throughout it's life. I rechecked the timing...spot on.

 

[Don S]

Re: Merc. 3.0 points too close?

You need to verify your point gap by checking the dwell. I know a few people that can set gap and get the dwell close, but they do it for a living and they also check with a dwell meter. I find very few first timers with points that get the gap right.
Once you have that, you set the timing.

Are you sure you have the Delco distributor? They use the .022 gap, the Prestolite uses .016.

 

[dswi]

Re: Merc. 3.0 points too close?

Don-I have no idea what distributor I have. I set the point gap at .018 as per "info for DIYers" on this forum. And according to a local "boat guy" that has been doing boats for 35 years (owns a "boat junkyard" not far from here).
I hooked up the timing light and the notch on the pulley was about an inch or 2 from the jagged edges where marks are (in the BTDC direction).
I "timed it by ear". Loosened the dist. and turned it until bad running to the left, then to bad running to the right...Split the difference and it seems to run great (and crank a lot easier)...
I don't have a dwell meter though...
I am thinking about replacing the points (OEM) and doing the timing all over again.
I don't know how much of a good idea "timing by ear" is..Any comments?
(I am an air compressor Technician / mechanic for a living, and am VERY mechanically inclined--I don't know if this will change your answer or not...)

Thanks
Darrin

 

[Fishermark]

Re: Merc. 3.0 points too close?

I hooked up the timing light and the notch on the pulley was about an inch or 2 from the jagged edges where marks are (in the BTDC direction).

What rpm was the motor running?

I "timed it by ear".

If you have a light, why time it by ear? Are you saying it wouldn't run when you timed it according to the specs?

 

[dswi]

Re: Merc. 3.0 points too close?

Running about 900-1000 RPM

While using the light, the notch did not line up...It was about an inch or 2 from the marks.

Found out today while skiing that the "shudder" on take off did go away...That's good.
I am thinking about changing the points anyway (just in case they haven't been changed in a while).

 

[Pete104]

Re: Merc. 3.0 points too close?

You will need to know what distributor you to get the correct points, ya know?!

 

[LAC_STS]

Re: Merc. 3.0 points too close?

There should be numbers. Not a notch when you use your timing light.

You can get some auto electrical meters that have a dwell setting. I got one for $55 on eBay
and it works same as an old analog one I have.

You HAVE to use the dwell meter AND timing light to do this. I was WAYY off with the feeler gauges the first TEN times I tried. You will never know for sure if you have or don't have it right.

And you have to start knowing for sure what's not wrong so you can find what's is wrong.

 

[LAC_STS]

Re: Merc. 3.0 points too close?

And you risk damaging your engine if you are running widely off timing.

 

[dswi]

Re: Merc. 3.0 points too close?

Thanks for the good advice. I will take heed of it...

How hard (just a thought) would it be to change from a points system to an electronic ignition system?? Or is it doeable?

 

[LAC_STS]

Re: Merc. 3.0 points too close?

I am not 100% certain what is required because I do not know your engine. But generally yes and they make conversion kits that replace the points in your dizzy without having to replace the entire dizzy.

Once you get A dwell meter and do it a couple times you will be good. It's not hard at all once you know how.

And if you get an auto elec meter with dwell you can use t to check other things on your engine. A must have if your gonna be working on your engine. And you kill two with one stone. Elec meter and dwell meter.

 

[Eric 3.7LX Alpha 1]

Re: Merc. 3.0 points too close?

What year is you 3.0? post a pic of the distributor and someone will tell you which one you have.

Do it right and be safe on the water. There is no reason to time an engine by ear and risk any damge to the engine with detonation, which WILL happen if the timing is off while under load and under way.

edit... just read you previous threads... and yours is an '89....

here's a link to manual#10
http://boatinfo.no/lib/mercruiser/manuals/mercruiser10.html#/0 (first page)
http://boatinfo.no/lib/mercruiser/manuals/mercruiser10.html#/134 (Chapter 4B: ignition system)

 

[dswi]

Re: Merc. 3.0 points too close?

And if you get an auto elec meter with dwell you can use t to check other things on your engine. A must have if your gonna be working on your engine. And you kill two with one stone. Elec meter and dwell meter.

I have several Fluke meters...Could there be an adapter or something that will make the fluke meter do dwell?

 

[Don S]

Re: Merc. 3.0 points too close?

I have several Fluke meters...Could there be an adapter or something that will make the fluke meter do dwell?

No. You need a dwell meter, a timing light, and a service manual or you are just randomly throwing parts at your engine without a clue what you are doing.

Without know what year, serial number, of your engine, or what distributor you have any answers to what you should do is impossible.

 

[Oshkosh1]

Re: Merc. 3.0 points too close?

I "timed it by ear". Loosened the dist. and turned it until bad running to the left, then to bad running to the right...Split the difference and it seems to run great (and crank a lot easier)...

Ensure the "0" mark is truly MECHANICAL TDC also. Verify it by getting #1 to compression stroke and see how things line up.

You can purchase a reasonably priced dwell meter, and if you stay with the points you'll find it useful in the future.

 

[dswi]

Re: Merc. 3.0 points too close?

Went to Sea Ray of Charleston (SC) and got plugs, gaped them and installed them. The old plugs I pulled out seemed to be burning correctly, but were gaped at about .028 when the spec is .022
I am heading to a friends place tomorrow that has a dwell meter and works on engines for a living. I will let ya'll know how thing come out.

What would the plugs being gaped too much do to the running of the engine??

 

[Eric 3.7LX Alpha 1]

Re: Merc. 3.0 points too close?

They may have been gapped correctly at one point and the larger gap is the wear on them.

 

[dswi]

Re: Merc. 3.0 points too close?

I assume that the increased gap would cause hard starting, shuddering when taking off from a stop, and such...Is this correct?

 

[fishrdan]

Re: Merc. 3.0 points too close?

Adjusted the points to .022 as per air filter cover says.

The old plugs I pulled out seemed to be burning correctly, but were gaped at about .028 when the spec is .022

Sounds like you are getting things mixed up, the plugs should be gapped at something like .035",,, maybe .045" depending on your ignition system. I'm not sure how the plugs got gapped at .28 as the gap grows bigger as the plugs wear, could be that they were never gapped properly when installed in the past.

Anyway, you are going to need to remove the plugs and gap them again, to the correct spec, what ever that is for your engine... Year and/or serial number of engine, type of ignition???