1993 Evenrude 48 SPL timing

[midstreamservice]

Mod. no VJ50TLETF. Boats.net states on their website to set the timing at eight degrees BTDC, but does not say at what RPM. Does anybody know?

[Joe Reeves]

I retired in 1991 so I have no knowledge of your engine's timing... BUT... I can say that having a engine timed at 8 degrees make no sense to me at all.

There would be an "idle" timing, and a full spark advance timing.

The idle timing is made when the scribe mark on the metal cam is dead center in line with the throttle cam roller.

Pertaining to the idle timing.... The synchronization of the linkage between the carburetors must be such that the butterflies open and shut completely at the same time. You do not want the butterfly of one carburetor shut with the other one slightly open! ,,,,,, The butterflies should just start to open when that scribe mark is dead center with the roller.

You can set the full spark advance with the following information if you wish.

Visit your dealership and get the actual degree setting for the following of that engine:

1 - Idle Timing
2 - Full spark advance Timing

(Timing At Cranking Speed 4°)
(J. Reeves)

NOTE: If your engine has the "Fast Start" feature", you must disconnect/eliminate that feature in order to use the following method. The "Fast Start" automatically advances the spark electronically when the engine first starts, dropping it to normal when the engine reaches a certain temperature.

The full spark advance can be adjusted at cranking speed,"without" have the engine running as follows.

To set the timing on that engine, have the s/plugs out, and have the throttle at full, set that timer base under the flywheel tight against the rubber stop on the end of the full spark timer advance stop screw (wire it against that stop if necessary).

Rig up a spark tester on the #1 cylinder plug wire. Hook up the timing light to the #1 plug wire. Crank the engine over and set the spark advance to 4° less than what the engine calls for.

It's a good idea to ground the other plug wires to avoid sparks that could ignite fuel that may shoot out of the plug holes. I've personally never grounded them out and have never encountered a problem but it could happen.

I don't know the full spark advance setting your engine calls for, but to pick a figure, say your engine calls for 28°, set the timing at 24°. The reasoning for the 4° difference is that when the engine is actually running, due to the nature of the solid state ignition components, the engine gains the extra 4°.

If you set the engine to its true setting at cranking speed, when running it will advance beyond its limit by 4° which will set up pre-ignition causing guaranteed piston damage! You don't want that to take place.

No need to be concerned about the idle timing as that will take care of itself. The main concern is the full advance setting.

A fellow member from one of the various marine forums suggested having water supplied to the water pump (flushette or barrel) simply to provide lubrication to impeller. A worthwhile suggestion I thought, and entered here.

Be sure to use your own engines spark advance settings, not the one I picked out of the air here in my notes.

[midstreamservice]

Thanks, Joe. I'll try to find out what the full advance setting should be.

[midstreamservice]

I get 4 degrees at idle and sixteen degrees at full throddle with no adjustments. I'll have to assume this is right. I can't get the dealer to answer the phone. They must be busy.

[midstreamservice]

4 Degrees at cranking speed with the cam as far back as it will go that is.

[Joe Reeves]

Try the timing degree questions on www.MarineEngine.com and www.iBoats.com if nobody jumps in here with the answer.

[midstreamservice]

Thanks Joe, but I have been to both. I'm taking the boat out today to see if it runs any better after adjusting the throttle linkage and installaling a new throttle cam. Before the butterflys would open only about half way, and the boat took about fifty yards to finally plane off. I'll let you know how it runs.

[Joe Reeves]

Thanks Joe, but I have been to both. I'm taking the boat out today to see if it runs any better after adjusting the throttle linkage and installaling a new throttle cam. Before the butterflys would open only about half way, and the boat took about fifty yards to finally plane off. I'll let you know how it runs.

The butterflies should just start to open when that scribe mark is dead center with the roller.

I never heard of anyone needing to install a new cam. This mention makes me wonder if your engine has that new "improved" cam roller.

That roller for many years (since day one) has been a one piece roller (3/8"). Some engineer in his brilliant line of thought decided to make that a two piece roller (junk) such as a much smaller rubber roller (1/8") surrounded by a clear plastic cover. This sets up a scenario whereas the clear cover breaks, falls off, and results in a wrong adjustment between the cam and the roller.... making it impossible for the butterflies to open at their proper time or to open fully.

The resulting smaller roller also affect the synchronization and timing so check to see if that roller is 3/8" diameter in size or 1/8".