Timing issue

[Mani]

I recently put in a new coil and electronic ignition kit in my 86 Supra with the 351W. I can't get this boat to time properly for the life of me. It ran just fine when I first installed it. I hadn't run it in about three or four weeks by that time.

I got it timed pretty darn close, and I ran it for about 10 minutes on the hose. As soon as I got it on the lake it ran rough and wouldn't go anywhere past idle. I could get it in gear, but no more than just idle or it would die.

We limped onto the trailer and got it home to work on it some more. I went through and double checked my wiring. Everything looks good. I pulled the distributor cap and went over everything again. Still good. I tried every timing position on the distributor and I can get it running smoothly, but only for about four to six seconds before it dies like there's no fuel getting to it.

I pulled the fuel line and there's plenty fuel getting through to the carb, and the choke plate is fully open, butterfly valves are closed at neutral. If I prime the carb it runs for the few seconds, but won't start otherwise.

Any suggestions on what might be going on inside the carb?

[beast 496]

What do you mean "every timing position"? You are using a timing light on the #1 cylinder, correct 10*btdc is proper. Al

[jet]

Like I said..doesn't sound like a timing issue. Use carb spray and spray a shot into carb and start the eng. When it starts running spray a shot into the carb every other second to keep it running,,if it keeps running look to the carb or the lines as the problem. You should check the gas line pressure by a gauge..6-10 psi I think?? Or you can buy a gauge and install it between the pump and the carb..this is the best way for a boat that way if you get stuck out on the water you can look at the gauge and no instantly that that's not your immediately problem and move onto the next item. Good luck man..or Mani. lol Jet

[DKJBama92Mariah]

What do you mean "every timing position"? You are using a timing light on the #1 cylinder, correct 10*btdc is proper. Al

Al is correct here. Also note that #1 cylinder on the 351 is the frontmost cylinder on the starboard bank. This is exactly the opposite of a GM motor where #1 is frontmost on the portside bank. Using a timing light (a cheapo basic unit from autozone works great for me). Just winging it is not a good option. Like Al said, set the timing at 10 degrees BTDC.

I'm thinking it may be carb rebuild time. Sounds like an idle fuel feed passage is clogged.

[Mani]

I already borrowed a timing light and tried using it to time the engine with no luck. The carb was professionally rebuilt about 4 months ago, but i wouldnt rule it out, as the fuel accelerator was leaking when I got it back. Might be another one of those issues.

[jet]

Mani..I can time my engine with my eyes closed and with a beer in my hand and get it almost spot on with no timing light, and even though your carb has been rebuilt doesn't mean you can't have a problem there or just a fuel delivery prob. When you say you can't get it to run in any position..there is something else wrong?? Need to look else where?? That's why I was puzzled the other day. Keep looking..

[DKJBama92Mariah]

Mani, when you say you put in an electronic ignition kit, are you saying that you replaced the points on the distributor with an electronic conversion or did you go with a whole new distributor. In either case, did you remove the distributor from the engine for the swap, or just pull the cap and replace the guts with it left in the motor?

The reason I ask is, it is possible to install the distributor with the gear advanced or retarded one tooth and the engine will still run, just barely though. If this is the case, it would be possible for the engine to run without a load with the distributor twisted an extreme amount in one direction or the other. I would expect it to die as soon as a load is placed on it or when revved very high. If the distributor is off by one tooth, attempting to set the timing with a light would be fruitless.

When you say it ran fine three or four weeks ago, was that an on the water test or simply running on the trailer?

Also, if you replaced the cap and wires, double-check and make for sure you got the firing order right.

[Mani]

Derek, I just pulled the guts. I'll give your method a shot tomorrow or Friday. I hope that's all it is. This is the first problem with this boat thats giving me serious trouble. Usually its pretty straight forward.

[cadunkle]

What is your initial timing set at when you set it in the driveway and it idles fine? What is it set at after it runs poorly? Can you see the timing wander at all? If you set it, then rev the engine and let it return to idle does the timing ever return to a different setting?

When you installed the points eliminator did you ensure the mechanical advance springs are both intact? If one is loose or damaged you will get erratic timing. How many hours on the engine? High hours could mean a worn timing chain which would result in erratic timing. Without disassembly you can turn the crank one direction then the other while watching the rotor, the rotor should turn quickly after reversing rotation on the crank. A long delay indicates a worn timing chain.

[DKJBama92Mariah]

Mani, you may have misunderstood me. If you didn't pull the distributor and the boat ran fine before the upgrade(or at least ran fine until the points failure leading to the upgrade, then you have no worries of the distributor being out of time. Please clarify that point.

If you did pull the distributor then let me know and I can explain the procedure for finding the right tooth for the gear.

cadunkle has offered some sound advice as well. You should definitely perform his checks on the advance weights and springs as well as his test for timing chain slop.

EDIT: Also, if you didn't replace the cap and rotor when you did the upgrade, you should do so now.

[mysledblows]

I fought a timing issue with mine for a year after I bought it. Guy I got it from didn't have the wires right. I set them as was printed on the tag on the motor. Ran worse. Turns out that the tag was for a different firing order than the motor that is in the boat. It would run fine on the hose (though not right) but in the water it wouldn't get out of it's own way. Right hand tag on a left hand motor. Oddly enough 5 of the them are the same either way, but getting the other three right made all the difference. Might be your issue.