Timing Puzzle

Just for the heck of it try pulling off one plug wire at a time & see if any one wire changes the idle quality more than another.
I looked at a southwind for sale that "only needed a tune up" it ran like crap-stumbled & idled poor. The guy let me bring it home to slap a tune up on it ( plug ,wires ,rotor,cap ect.) After the plug wire trick I found the cam lobes wiped out on the #1 cyl. I payed for the tune up and he took the boat back! I hope it's something less painful than a rebuild.

You got guts to open your motor box and put a timing light on the engine while running AND pulling a skier no less....

Wow.

I can't do it.

I can't even imagine it: "Here, put these gloves on. I'm going to time my engine while I'm pulling you."

jefmar wrote: Thanks for writing in everyone. Anyone have success with the ebay New Old Stock (NOS) Prestolite distributors?

Yes, that is where I purchased my NOS Prestolite (screw down cap) distributor. It was indeed unused and in perfect condition. I did open it up and check it out for dust bunnies and surface rust. Blew it out with compressed air and re-lubricated moving parts.

Thanks for writing in everyone. Anyone have success with the ebay New Old Stock (NOS) Prestolite distributors?

David – Yes, same deal, glad you wrote in. And glad you checked the carb too. I also by trial and error adjusted the initial timing to find a balance between no stumble and hard starts. The boat runs t*ts other than that. I will continue to figure this out until it is perfect.

I thought it could be something with the engine that is causing the timing to retard at higher RPMs. Possibly a sloppy timing chain or worn cam gear or something?? Couldn't be two bad distributors right?? I checked for slop between the crank shaft and rotor by rotating the crankshaft back and forth with a wrench and watching the rotor move – it was tight with 5 degrees slop measured at the balancer. The gear on the cam shaft looks perfect. And #1 piston at TDC lines up with the timing 0 degree mark.

I suspected two bad distributors but to be sure, I went to a high performance shop with a distributor machine and had the ebay New Old Stock (NOS) distributor spun. They found that the distributor goes up very fast to 12 degrees advance, stays at 12 degrees advance until about 2800RPM, from there it goes linearly to 20 degrees max at 4600RPM. Per my previous post, when I set the initial at 10 btc, I saw 22 btc at 2000 through 3000RPM (12 degrees of advance). So it looks like it matches and the distributor is to blame because there should be 22-24 degrees of advance at 3000RPM. The hipo shop agreed that the curve is not good.

The hipo shop can tune it to what I want but I am concerned that I might have to pay more to have them curve it again if it is not perfect. I can buy spring kits for aftermarket and change it myself.

So I’m in the market for an aftermarket distributor, leaning towards the Mallory points version for $135 because spring kits are easy to find and I am cheap… But that got me into trouble with the ebay purchase already!

no the idle mixture screws won't effect anything off idle and the floats could have been a little off and need adjusting, but since all of that didn't effect it or solve the problem completetly, then I would went straight too the mechinical advance, well no first I would have checked the timing at 3000 rpm and verified it was in the low 30's but then again I would have done that when I set the timing the first time, so ya I would have gone sraight the the mechanical advance, but wait maybe I would have looked at the carb a little more first and verified that the secondary's where opening up correct, rthen went to the timing.

Not everyone does things the same way some stand in the wind and try not to get wet other diagnois the problem and then find the issue causing it and fix the problem instead of covering it. It's one thing to get it running long enought to get rid of it...it's a completely different story fixing right so that you don't have to worry about it.

then again you could just hit the carb with your hammer some more and hope that fixes the problem. Stick to fixing fiberglass

This place is better than a bar on Friday night.

You know, he could have both problems. He needs to get his carb and his timing right.

David I agree with your posts 99.9% of the time but I think this boy needs a timing light. Setting the timing with a light is easy. Once the timing is set attack the carb. In my mind, you should do it in that order.

instead of adjusting the carb to fix your other issues when the timing is set correctly, you choose to mask or hide the effects be advancing the timing and ignoring the real problems, thus you sacrifice maximum performance and fuel ecconony for being lazy

so in other words your not very good at adjusting a carb either.

I guess I've never seen a carb that you could take out of the box, bolt on to the engine and only have to adjust the idle, very foolish thinking to me. I've always had to inspect and adjust the linkage, idle air screws, float levels, idle and the throw of the accelarator pump. So If your saying that it runs fine at 20 degrees of timing and comes out of the hole without stumbling as well then something is way off or you have a bad harmonic blancer giving you a false timing reading but I doubt it since it doesn't crank right, so I'll assume that you still have the stumble at 20 degrees of timing and the stumble coming out of the hole is caused by accel pump being out of adjustment 9 out 10 times. The pumps not bad, it's just squirting too much or too little gas, to soon or too late causing a stumble.

Thanks for your input 79 but I will not give up and take it to a mechanic yet. I just purchased and installed a new carb; nothing changed when it was installed. If the accelerator pump is to blame, then the old carb and the new carb both had accelerator pump issues.. this is doubtfull. Changing springs in the Prestolite distributor is easy but finding springs for it is not.

I bought and installed a new old stock prestolite distributor off ebay. Here is a link to the completed auction.

.Purchased Distributor

Unfortunately it did not solve the problem. At 10 btc initial it still stumbles in the water out of the hole. At 20 btc initial it runs very strong at any RPM but starting it is a little difficult as it requires pumping the throttle to get it started. Setting it back to 10 btc, it starts perfectly. Here is the rough timing curve measured:

700RPM - 10 degrees
1500RPM - 20 degrees
2000RPM - 22 degrees
3000RPM - 22 degrees

I am thinking that Mallory MAA-YLM554CV will provide the advance curve (and adjustability) that I am looking for but it seems strange that two distributors have the same problem and something else might be going on.. Any suggestions before I spend more money and buy the Mallory?? Thank you for your help.

Thanks 79, The PCM repair manual labels the posts that hold the springs as "advance adjusting brackets". I bent them a little to put more/less spring pressure at rest.

79 - I went to a couple autoparts stores and neither had springs. I lubicated the assembly and tried adjusting the advance ajusting brackets in the distributor. I bent the brackets to engage the springs harder and I had no advance at higher RPMs. I bent the brackets the other way such that the springs were loose when starting and I get the same curve as before. I'm thinking I need a new distributor or something else is wrong. Do you agree? I noticed in your other posts that you suggested a new prestolite distributor on ebay.. Do you think that my electronic ignition conversion kit would fit in those ebay Prestolite distributors? I'm also considering Mallory.

SS-201 - I have essentially done that already. I'm only getting 12 degrees max advance so when I had the timing 18 btc at 600RPM, It was around 30 btc (18+12) at 3000RPM. You mention the chain..

79 & SS-201 - Do you think the timing chain could have something to do with this? I'm only getting 12 degrees advance max.. I possibly could pull my distributor and have a shop measure how much advance I should see in the boat. If the shop measures 25-30 degrees max advance then the distributor is okay.. and possibly the timing chain is to blame.. Does that make sense? Or should I just buck up and buy a distributor?

Thanks 79, I'll give it a shot