Delco EST distributor issue

[cj7ole]

Boat is a 1989 Malibu Skier with the Mercruiser Comp Ski 5.7 engine, 700 hours. Rochester carb and a point distributor. After a head replacement due to overheating I lost 800 rpms, used to get 4400, now only 3600. Based on the bad advice of a mechanic ("you need 36 degrees of advance, you are getting only 24, that's your problem, you should replace that Prestolite distributor"), I purchased and installed a Delco EST distributor kit. Since found out that 24 degrees is correct.

I set the initial timing with the "initial timing harness" to 8 degrees BTDC at idle. When I remove the harness, the timing goes to 20 degrees at idle and the idle speed becomes erratic, and on a test run went from the spec 620 rpm to about 1000 rpm constant. Advance stays about 20 degrees all the way up to 3000 rpm at the dock.

Whats up with this? Any suggestions? Should I just tweak the carb throttle stop idle adjustment? I am afraid if I do that I will have starting problems.

Oh yea, at WOT, I still get 3600 rpms. Replaced the fuel filter. I suppose it could be a carb problem. I can't smell it, but some skiers say they can smell gas while skiing. Just smells rich to me, like cars before all the emissions control.

 

[cj7ole]

Re: Delco EST distributor issue

Bump... Anybody? My granddaughter is looking to go tubing with our stretch of warm weather.

 

[Bondo]

Re: Delco EST distributor issue

Ayuh,... The timing Should jump after it's Set, 'n the jumper is removed,...
I donno the specs on those, so I can't really say,...
I'd let go of the dock, 'n run 'er up to wot, to see what it does...
I'd expect to see 30/ 32?, all in by 3000/ 3200 rpms,... Donno...

Just bring the idle down on the carb linkage...

I'd probably Bet on most of yer issues being carb related, or atleast fuel delivery related...
Rochester, 'n points says she's Old...
Any crud in the filters,..??

 

[Indymike]

Re: Delco EST distributor issue

After putting an EST in my boat , I would not recommend one for a V8 carbed motor. It took three different modules for me to get the ignition to advance.
I had to set initial up to 12* to get the total timing to 32*. And as you stated it ran very erratic at idle.

I talked to a couple of ignition guys, and the opinion was that it is a very nice ignition, but it really needs a control module, to get the best from it.

 

[cj7ole]

Re: Delco EST distributor issue

After putting an EST in my boat , I would not recommend one for a V8 carbed motor. It took three different modules for me to get the ignition to advance.
I had to set initial up to 12* to get the total timing to 32*. And as you stated it ran very erratic at idle.

I talked to a couple of ignition guys, and the opinion was that it is a very nice ignition, but it really needs a control module, to get the best from it.

Oh, boy, here we go...ugh. Well, thanks for the response.

I have had it on the lake, seems to run fine up to the 3600 rpm I was previously getting. Idle is spec until it really warms up, then it goes to nearly 1000 rpm. Good thing I have a real tranny that doesn't grind gears like an I/O when you engage it at 1000 rpm.

 

[Don S]

Re: Delco EST distributor issue

Seems to me like everyone with a Mercruiser wants the EST distributor to do exactly what their previous system did. Rather it be points or Thunderbolt.
Hate to tell you this guys,. but it's not going to happen. The EST is different, and until you understand how it works and what does what when, you're just a bunch of shade-trees trying to put specs on something that cant be done.
It's amazing that GM used the EST, as well as Volvo, and several other marine engine marinizers that use the EST with no problem. It's only those trying to make an EST do what other systems do that have problems.

 

[cj7ole]

Re: Delco EST distributor issue

Maybe I missed something, but in all of the searching I did regarding distributor replacement on Iboats.com, until this thread (which almost died) everything pointed to changing over to the EST system. Could be I latched onto someones suggestion and ran with it. If so, my bad. Maybe a 7 year old post I read suggesting it could really only work with a computer was correct.

So, will someone please point me to where I will learn to "understand how it works and what does what when"? That is so I can decide whether I can make it work or if I need to suck it up, put the EST up on CL and put my old distributor back in. And then explain it to the wife.

By the way, none of the instructions or posts I read on installation even discussed connecting it to an engine control or distributor module, I was led to believe it was a simple replacement for a points style distributor. And that is someone else's bad if Don is correct.

 

[Indymike]

Re: Delco EST distributor issue

Seems to me like everyone with a Mercruiser wants the EST distributor to do exactly what their previous system did. Rather it be points or Thunderbolt.
Hate to tell you this guys,. but it's not going to happen. The EST is different, and until you understand how it works and what does what when, you're just a bunch of shade-trees trying to put specs on something that cant be done.
It's amazing that GM used the EST, as well as Volvo, and several other marine engine marinizers that use the EST with no problem. It's only those trying to make an EST do what other systems do that have problems.

I can't disagree at all with this. But the EST is advertised as a direct replacement.
My buddies volvo 5L carbed motor runs flawlessly with the EST.
Whats different? I don't know. But would like to.

There are a lot of folks out there with old worn out corroded ignitions looking for a solid cost effective replacement.
Whats the answer?

 

[Don S]

Re: Delco EST distributor issue

Whats different? I don't know. But would like to.

Volvo doesn't have Thunderbolt ignition. .

 

[Indymike]

Re: Delco EST distributor issue

Volvo doesn't have Thunderbolt ignition.

Please explain. I understand its not a thunderbolt.

His volvo has the EST and it works pefect.

 

[Don S]

Re: Delco EST distributor issue

Prior to the EST, Volvo used the Prestolite BID distributor with mechanical advance.

 

[Indymike]

Re: Delco EST distributor issue

Gotcha. I think.
His EST was factory installed. Not a replacement.
About 2004 SX

What needs to be done if its not really plug and play.
I understand the timing method.

I am considering the pertronix mech advance unit.

 

[Don S]

Re: Delco EST distributor issue

Enough of the hijack, start a new thread with your question.

 

[Indymike]

Re: Delco EST distributor issue

Sorry.

New thread.
http://forums.iboats.com/showthread.php?t=495783&p=3345429#post3345429

 

[cj7ole]

Re: Delco EST distributor issue

So, do you think I (the OP) have a bad module if the timing jumps from back and forth from 8* to 18* at about 700 rpm (nothing in between)?

 

[cj7ole]

Re: Delco EST distributor issue

Update:

I called Marine Engine Depot and talked to Lee. Based on that discussion, I got a timing light with advance ($30 at HF) and verified that I was getting 26 degrees of advance at anything over 1000 rpm. That is obviously not the correct advance curve. He will get me a new distributor to try.

 

[cj7ole]

Re: Delco EST distributor issue

Got the replacement distributor installed and it, too, has the same issue with anything over 1000 rpm going to 26 degrees of advance. I have searched to try and find anything about how the EST is supposed to work with no luck. Does anyone know if this is typical for the Delco EST distributor?

 

[Don S]

Re: Delco EST distributor issue

Just to make sure I have this right. When you are not in base timing mode and the timing connector is removed from the distributor completely, at idle the timing jumps around btween 8 and 10?. Then, when you raise the rpm to 1000 rpm, the timing jumps to 26? and is steady at that point and does not increase any more with more rpm. Is that correct?

What are you setting your idle timing at?

 

[fishrdan]

Re: Delco EST distributor issue

Got the replacement distributor installed and it, too, has the same issue................

One question, did you remove the resistor wire for the points ignition, or run straight 12V to the new EST ignition? I'm not sure if low voltage would cause the quick advance problem, but if 2 new EST's are doing the same thing, I'd think it has something to do with your particular setup.

(BTW, I'm running an EST on my 140 4cyl, works great.)

 

[cj7ole]

Re: Delco EST distributor issue

Just to make sure I have this right. When you are not in base timing mode and the timing connector is removed from the distributor completely, at idle the timing jumps around btween 8 and 10?. Then, when you raise the rpm to 1000 rpm, the timing jumps to 26? and is steady at that point and does not increase any more with more rpm. Is that correct?

What are you setting your idle timing at?

Don, Yes that is correct. Base timing with the harness in place is 8 degrees. When I shortened the wire to the old distributor, there appeared to be what I believed to be a resistor or fusible link in the portion I removed. I will verify the voltage tomorrow. Actually, I could live with the engine's performance as-is up to 3500 rpm, it is a little sluggish, but that could be the carb, as I am still struggling with the 800 rpm loss at WOT, low idle at 580-600 rpm is steady, I just have an issue with an uneven idle between 700 and 1000 rpm when the timing jumps. Things could be worse, but it just doesn't seem like how the distributor advance should be working.