Distributor problems.

[Canuck Sailor]

Hi - still troubleshooting Chris' engine. Looking at the distributor now. What symptoms would issues with the flyweights create? I'm thinking the flyweights might be rusty, or sticking. He does have electronic ignition.
Next, the coil. If there is a problem with the coil, how would it show up?
This is the original distributor we believe. Could there be a problem with the gears at the bottom of the distributor shaft?
Basically, I'm looking at any possible problems centered around the distributor and looking for suggestions.
Thanks.

[Al Schober]

The flyweights and their springs control the centrifugal advance. At idle, the spark occurs close to top dead center. As the engine turns faster, the fire needs time to get going so the spark occurs sooner (before TDC). Clean up the rust and install new springs. Unlikely the drive gear is an issue.
Check the shaft for excessive side play. You don't want the rotor hitting and damaging the cap. Check the cap for chips/cracks.
With EI, the condition of the cam is not an issue. Your coil should be the one recommended by the maker of the EI.
Bad coil will produce no/erratic spark. Typical and common failure is no spark when the coil is hot, works again when it cools off. Leaking oil is not a good sign.
Ignition timing is typically set to TDC at idle, then refined when the boat is at cruise speed by tweaking the distributor to get max RPM. Shouldn't take much if the advance is working properly. A big tweak or an engine that won't idle after the tweak is a sign the advance isn't working as it should.

[campbdon]

Al, in your opinion would it be considered valid to refine the timing for cruising speed while tied up to the slip? I Prefer not to try this on open water since I don't have someone to keep watch while I tweak.
Thx, DonC

[Dave Neptune]

If the weights (c-advance) are stuck open (advanced) the engine will be hard to start and run very rough at idle AND run OK when revved up under load. If stuck closed (full retard) it will start and idle fine but very little power and rough running as you apply throttle under load.

Can you twist the rotor and when you did did it spring back? If so it should be considered OK.

Does the engine have points or E.I.? If points the timing will change as they wear however not drastically. With the E.I. the timing only changes if you move the distributor.

Dave Neptune

[Al Schober]

Don,
If you can't do it under way, you're probably better off with a timing light and reving it in neutral - verify that the spark advances as the RPM increases. No need to load up those old frayed dock lines (grin).

[campbdon]

Thank You Al. I was intending to follow the "static timing" procedure as per DonM's video (https://www.youtube.com/watch?v=2ysFGcm8oNo), meaning aligning the flywheel to #1TDC, then rotating distributor housing while watching a continuity test light (connected across the coil leads). Is there a video on this site for adjusting the timing using a strobe light? That's the type of test you prescribe while in neutral ?? BTW I have EI installed.
DonC

[Dave Neptune]

Setting the timing with an E.I. is pretty much a one time deal unless you need to remove the distributor for some reason.

Get the engine to TDC as best you can, many ways to do it. Once achieved make a mark on the accessory drive and align with a pointer held by a hose clamp. Now from the TDC mark put another mark 15/16" before the other. Thatch will correct me if the 15/16" is off but I think it is the number we worked out years ago to represent the 17* of distributor advance which works out to be 34* total. The A-4 seems to run best with a full advance of 34* of advance.

The 34* of advance should happen by around 1600 RPM's and can be easily confirmed with the marks and lite. Once set you may need to adjust a few degrees in either direction for best performance on your boat.

Don't do any of the above until the centrifugal advance is working smoothly, IE the rotor twists easily and returns smoothly. Also I can't recommend enough that you "spring" for the new springs which work much better with the E.I. as the drag against the advance of the points is now eliminated.

Dave Neptune

[Al Schober]

No, my suggestion for the timing light was just to verify that the centrifugal advance was working.

[JOHN COOKSON]

IE the rotor twists easily and returns smoothly. Also I can't recommend enough that you "spring" for the new springs which work much better with the E.I. as the drag against the advance of the points is now eliminated.
Dave Neptune

This takes sort of a feel to know what is right. For many years (pre forum days) I "checked" my advance by twisting the rotor. It always sprung back so I figured the advance was OK.
The first time I took the breaker plate off, what a mess. One spring was broken and there was a lot of corrosion around the weights. I ordered new springs and cleaned and lubed the flyweights. There was a day and night difference. The engine ran like it just had a super tune up.

ex TRUE GRIT

[Mo]

Here is what I do and it's something I picked up off this forum...I just don't remember who from.

1. ensure ignition components are in good shape as well as the centrifugal advance springs and light lubrication of those.
2. I leave the boat tied to my dock and run it up pretty good (no tach) and set the distributer to where she has highest rpm engine sound...then I back it off just a tiny bit and steady up the bolt holding the dizzy.
3. Next I take the boat out and set her running at the "normal boat speeed" that I usually motor at....about 5 kts for me. Then I loosen the dizzy bolt again underway and swing it a little...once I find that perfect spot where she sounds good, rpm is highest, I lock it down.

Note: I use NGK XR4 plugs, raw water cooled, no T-stat with by-valve open half way. Plugs are new except for no. 4 which the new one failed, replaced with another new one which was no good...put one of my old ones in and it runs great. So why did I add this?

For the past 2 weeks I've been checking my hours running and fuel used...when I had that plug issue I was sucking fuel so that's why I started checking and measuring what I added to bring her to the top of the fill neck. For the past couple of weeks I'm burning 2.5 litres an hour... so that's just over 1/2 a US gallon. My previous engine sipped fuel as well....once they are opened up, full throttle, of course that is out the window and she's more like 3/4 a gallon an hour or more depending. I think the timing set while underway makes a huge difference.

EDIT: Friday night I towed an ODay 34 back in calm weather....his engine died, then the wind died, so he called me. Towed him about 4 miles with my throttle in my "5 kt" position and we maintained 4 kts all the way back...I haven't filled up since but I keep a note of hours and litres now just to figure out what this engine is doing. Some of you know this was a replacement engine that I put in last year so I still tweeking it a little.