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View Full Version : Anyone have a good photo of the 350 TBI timing marks?


Chicago190
06-27-2008, 12:52 PM
I'm having an intermittent starting problem that Vince at skidim said could be related to ignition timing being off. I've never adjusted timing before since I've never had a car with a distributor, but I think I understand how to do it. I'm just wondering if anyone has a good photo of the harmonic balancer and timing marks so that I will know what to look for.

jimmer2880
06-29-2008, 07:08 PM
I don't have a pic. However, before you try to adjust the timing on that boat, you need to get your boat into "diagnostics" mode. You can either get a device to do that, or jump across 2 of the pins. Don't ask me which 2 pins, but if you do a search on here, it's been posted before.

You'll need to be on 10deg Before Top Dead Center. Don't mess with trying anything else BTDT, it won't get you any more than what you'll get at 10deg.

Chicago190
06-29-2008, 07:25 PM
Its Pins A and B for anyone that reads this in the future, according to Engine Nut.

http://www.tmcowners.com/teamtalk/showthread.php?t=11254&highlight=timing

Chicago190
07-03-2008, 03:56 PM
Ok, I took a look this afternoon. On the pulley there is a 10 degree BTDC marker. There is also a 10 degree BTDC mark on the engine block as well. Both the marks have white out on them, so I assume to set the timing, I put the timing light on the pulley and line up the two marks?

JohnnyB
07-03-2008, 06:50 PM
Here's a thread I did with some instructions and pics when I set the timing on my 2004 PS 197 with TBI engine.

http://www.tmcowners.com/teamtalk/showthread.php?t=18827&highlight=timing+mode

JimN
07-03-2008, 07:11 PM
Look on the lowest pulley- that's the crankshaft pullet and on this, you'll find a line cit into the edge. That's Top Dead Center (TDC) and if you look at the front of the motor, next to the pulley is a metal L bracket with a jagged edge. Wipe off any grease, etc and shine a loght on it to see the marks. If there are no numbers, it'll have a line that designates TDC. Each peak is 2 from the next peak, so it's 1 to the adjacent valley.

As mentioned, A and B are the two terminals you need to jumper anda a paper clip works fine for this. Once you get it running (or, you can start it and jumper the terminals), you'll need to raise the RPM to 1000 for reading or setting the timing. I wouldn't advise just grabbing the top of the distributor cap to adjust it, expecially if the plug wires are older or it's humid. The coil puts out over 50K Volts and while it will definitely get your attention, it's not all that pleasant, unless you enjoy that kind of thing.

Loosen the hold-down bolt about 1/2 turn and make any changes needed, snug it and verify that the timing didn't change and tighten it the rest of the way.

If you use a timing light that has an adjustment for advance, you need to set the timing so the 10 mark on the pulley lines up with the 0 mark on the bracket. If you line up the mark on the bracket and pulley with a timing light that has no adjustment, you'll end up at 20 BTDC base timing, which is too much. If you aren't the original owner or it has been serviced at more than one place, it's possible that one had a light with the adjustment and one didn't, so they marked both 10 indicators.

What is the actual problem- cranks really slow and then spins like crazy or just cranks slowly?

Chicago190
07-04-2008, 11:53 AM
The problem is the same that you helped with before, but now I've done some research since I have time. I'll recap whats going on:

1. Boat starts fine cold and runs perfect when in gear.

2. Idle problem was not solved like I thought it was. The problem is in neutral, the engine RPM varies. This is especially pronounced after running at speed. After about 1 min. in neutral the idle seems to smooth out.

3. Exhaust smells rich at idle only after running at speed. Exhaust smell goes away as idle smooths out.

4. When warm, if the engine was turned off and then restarted after sitting for 1-2 mins. it would not turn over properly. The engine would crank, pause, crank, pause, crank, and then turn over 3-4 times and fire. I replaced the battery because it was old, so I'll see if that solves the problem.

Basically, the engine was just replaced and I wanted to check to make sure the timing had been set properly.

JimN, I don't think my timing light has advance, it just hooks to the battery and spark plug wire. Has a trigger and strobe, nothing else. What marks should I line up? I can clearly see all the marks, just need to know which to line up.

JimN
07-04-2008, 12:11 PM
If it doesn't have advance, mark the 0BTDC and with the ECM in diagnostic mode (paper clip), make sure the 0 mark lines up with the 10 point on the bracket. 0 is usually at a valley, so you want to go 5 valleys from 0. If it's at 6-14 BTDC, it'll still start and idle, but 10 is where you want it to be. The ECM will add advance when needed and the total it can add is 35, so you don't want to exceed 45 total advance (base timing + advance added by the ECM).

Remove the flame arrestor and watch the bottom of the injectors after shutting it down. If it drips, it's part of the problem. Your description does sound like excessive advance, though.

Chicago190
07-04-2008, 12:17 PM
If it doesn't have advance, mark the 0°BTDC and with the ECM in diagnostic mode (paper clip), make sure the 0 mark lines up with the 10° point on the bracket. 0° is usually at a valley, so you want to go 5 valleys from 0°. If it's at 6°-14° BTDC, it'll still start and idle, but 10° is where you want it to be. The ECM will add advance when needed and the total it can add is 35°, so you don't want to exceed 45° total advance (base timing + advance added by the ECM).

Remove the flame arrestor and watch the bottom of the injectors after shutting it down. If it drips, it's part of the problem. Your description does sound like excessive advance, though.

Thanks as always. The valleys/peaks on the bracket are marked with degrees BTDC so they are easy to identify. Already jumpered A and B yesterday and it raised the idle 1k RPMs so I know how to do that. I'll give it a try this afternoon and see if it was the problem.

JohnnyB
07-04-2008, 12:30 PM
Where are you around Minocqua WI?

Chicago190
07-04-2008, 02:56 PM
Where are you around Minocqua WI?

Lake Alva, in Harshaw. About 30 mins from Minocqua and Rhinelander.

Chicago190
07-05-2008, 03:14 PM
Problem solved. Timing was advanced to about 16 degrees BTDC, reset it to 10 degrees and the boat runs like new. Idle is rock steady, starts on the first crank, and no longer smells rich.