351W engine Timing advance 40 Degrees?

[Untamedpeppers]

I just installed a rebuilt 351W in 1980 Ski Supreme ( I know it is not a Mastercraft , but same engine, and if I’m correct Ski Supreme was almost a direct copy of Mastercraft at this time..couldn't afford the mastercarft )

To get the engine to run, I have to advance the timing 40 degrees. I’m trying to figure out why I have to advance it so much.

I have double check the spart plug wiring / firing order, pull the engine apart to check the time chain. I have no clue what else to check.

I did upgrade the point to the Pertronic Ignitor II and Flame Thrower Coil. My Volt Drop to about 9 Volt at the Coil when starting, would this change the timing?

[Laurel_Lake_Skier]

I just installed a rebuilt 351W in 1980 Ski Supreme ( I know it is not a Mastercraft , but same engine, and if I’m correct Ski Supreme was almost a direct copy of Mastercraft at this time..couldn't afford the mastercarft )

To get the engine to run, I have to advance the timing 40 degrees. I’m trying to figure out why I have to advance it so much.

I have double check the spart plug wiring / firing order, pull the engine apart to check the time chain. I have no clue what else to check.

I did upgrade the point to the Pertronic Ignitor II and Flame Thrower Coil. My Volt Drop to about 9 Volt at the Coil when starting, would this change the timing?

Changing the coil won't alter your timing. 40 degrees btdc is a lot of advance (even at WOT) and usually would cause problems with cranking the engine over for starting. I'd start with being sure you're connecting the timing light to the #1 cylinder (right behind the driver seat).

[CantRepeat]

I think total timing is something 36 or 38 at most. At idle I believe its 10 degrees.

[Spork]

...........

[Untamedpeppers]

Thanks for the replies.

The timing light was on the #1 cylinder, try two different timing lights just to make sure it wasn't the light.

It has an electronic ignitor.

I'll double check the harmonic balancer , but when the engine is firing its pushing back against the starter, so I think that the marks are right, but never hurts to check again.

Everything is the same from last year except I replaced the #8 pistion.

[paco_06]

Did this problem happen after the ignition upgrade? If so, double check the top plate position of the ei kit. It will only go in there two ways, one lh rotation, one rh rotation.

[catamount]

but when the engine is firing its pushing back against the starter

That's a classic "the timing is too advanced at ignition" symptom.

I would pick up a piston stop and find your EXACT TDC. I found that my balancer had shifted by about 10 degrees so I was getting VERY strange readings. Once I found TDC with a piston stop, I printed out my own timing tape and the boat is running better than ever. Don't use a "long screwdriver" method to find TDC, use a piston stop.

I wouldn't experiment with anything else until you find true TDC. Did you check the timing with a light last year before the rebuild? If not, the balancer may have been wrong all along and you're just noticing it now.

[Untamedpeppers]

Did this problem happen after the ignition upgrade? If so, double check the top plate position of the ei kit. It will only go in there two ways, one lh rotation, one rh rotation.

Install the Ignition upgrade last year and ran fine, but i did check it again and it was setup correctly.

Did you check the timing with a light last year before the rebuild? If not, the balancer may have been wrong all along and you're just noticing it now.

I used a timing light on it last year ( it was rebuilt and installed last year, put 8 hours on it before the seat fell out of the head, on to the piston and also bent the push rod )

Not sure about the Balancer, going to pick up a new one up tomorrow. (I believe it is that same as an automotive 28oz).

Also just thought about the gas has been sitting in the tank since last year, so going to try some fresh gas and see if it help. ( The engine won't crank at all now )

[Lincoln7]

The 351w in my 79 S&S is very similar in that it reads 27 degrees BTDC at idle. I am on the #1 wire so I'm thinking my balanced outer ring has slipped. It runs great: goes 46mph, 4900 rpm so I'm not too concerned. I will be verifying TDC with a piston stop soon. Please let us know what you find out.

[pbgbottle]

the only time i have issues like that is when i find the carb needs a rebuild ,a dirty carb can cause tons of problems with idle and timing .

[ssnaples]

I used to own an '81 Nautique with a 351W and the timing was 10 degrees BTDC at idle. Interesting to see that there are so many different responses on this.

You may want to ditch the Pertronix Igniter. I installed that same system on mine (ditched the points) and I had nothing but trouble. It would start, but fall flat on its face as soon as I hit the throttle. I tried everything you could possibly imagine without any success. I finally bit the bullet and bought a new electronic distributor (+/- $350) and everything worked like a dream. The flame thrower coil works fine though. Good luck!

[paco_06]

I used to own an '81 Nautique with a 351W and the timing was 10 degrees BTDC at idle. Interesting to see that there are so many different responses on this.

You may want to ditch the Pertronix Igniter. I installed that same system on mine (ditched the points) and I had nothing but trouble. It would start, but fall flat on its face as soon as I hit the throttle. I tried everything you could possibly imagine without any success. I finally bit the bullet and bought a new electronic distributor (+/- $350) and everything worked like a dream. The flame thrower coil works fine though. Good luck!

All my thoughts exactly, even same trouble with ignition conversion.