1986 Prestolite Advance Springs

[mckyle]

Alright, I've done about all the searching I can and am at my wits end. I believe my springs are bad and want to replace, but can't find any new ones for the life of me. I've also called around everywhere close-by and nobody rebuilds distributors any more. Any idea on where to get some? I've seen this kit by mallory: http://www.summitracing.com/parts/maa-29015 (see instructions as well) but I am not sure where timing should start (what deg at what rpm?) where it should slow down (again degrees btdc and rpm) and where it should end so I can plot the advance curve. The reason I'm thinking these are bad is that the larger spring does not stretch at all when I move the weights with my hand - like it's too loose? Also they're pretty rusty. Any help is greatly appreciated!

And that's WD40 by the way before I soaked up the excess from spraying it down. ;-)

[drschemel]

many machine shops can make a new spring for you if you are trying to avoid just buying a new distributor.

[mckyle]

can they do that by just looking at the old ones?

[mckyle]

If someone could help me plot out the advance curve i would greatly appreciate it. I particularly need the middle plot point where it slows down.

[j.mccreight@hotmail.com]

Originally Posted by mckyle

If someone could help me plot out the advance curve i would greatly appreciate it. I particularly need the middle plot point where it slows down.

First off I would actually check timing with a timing light and see if the timing is advancing. You might not have an actual problem with your distributor other than rusty springs. Base timing ~10° @ idle, full advance ~30° @ 3000 rpm Most of these spring kits will cause you to beat your head against the wall with trial and error. If you do need a distributor you just need to call prestolite and they can reman your distributor for ~$100 or sell you a reman already to go. There are several TT members that have gone through this. All in @ ~3000 rpm @ ~30° no need to worry about "middle of the road", as long as it operates smoothly between 10° & 30° your good to go. These are mechanical advance not vacuum advance distributors. If you have modded your engine and require more total timing I would suggest going with a mallory unilite or DUI distributor.

Mallory marine unilite 9-26501 is whats in my 351w.

[mckyle]

The reason I believe my springs are bad isn't because it isn't advancing - I checked with a light and it is. The problem is that when the boat is first turned on I've got it idling at about 600 rpm, but then after I bump the throttle a bit it never returns to that rpm... almost always about 750-800 rpm at least. The only way I can get it back to 600 rpm is when I turn the boat off then back on. That leads me to believe the springs are wore out and after it advances some the spring's tension isn't what it used to be and stays advanced on it's own until it's turned off.

Anyway - I found what I believe is the last place on the face of the earth that has the replacement spring kits for these distributors. I'll confirm once I get them, but here's to hoping. :-)

[thatsmrmastercraft]

Sounds like a fair chance the springs aren't returning all the way. Have you disconnected the throttle cable and checked to see if the cable is connecting the base idle speed?. It can be as simple as a sticky cable or a slight misalignment issue with your throttle cable bracket. I had to work with my bracket last year as it was binding slightly.

[j.mccreight@hotmail.com]

600 rpm should be idle in gear not neutral... most likely the rpm will be around 800 in neutral, I'm with mrmc check throttle linkage.

[TRBenj]

Checking the throttle cable isnt a bad idea... but it sounds like youve narrowed it down to a timing problem if you can shut down, restart and the idle returns to normal. I would be setting it to 650rpm in gear (600 is a bit low). Hopefully that translates to 700-750 in neutral. Too big of a differential would imply a misaligned powertrain.

Shoot for somewhere in the 20-24 degree range for the total advance. The 351w will like somewhere in the 34-36deg (total) for best performance. My boats tend to run best when set for 10-12 initial. Getting the curve dialed in can be tricky for sure.

Let us know how it all works out with the Prestolite spring replacement... and clue us in on your source if its legit!

[Cloaked]

A good while back someone here found springs here ==> www.dougrussell.com

No guarantees.

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