weird timing symptoms
 

Mercruiser 3.0 serial: D706324 EST Ignition (all new parts) Carb rebuilt. Starts on half a turn usually. Idles smooth, runs quietly.
My issue is that I am short about 800 rpm. I get on plane ok. I am propped correctly. I am also missing about 10mph on top end. I set the timing according to the proper method. It is right now at 0 Degrees BTDC (I think manual says I need 1 Degree BTDC). When I am on the jumper with switch bypassed, it doesn't sound any different than when it is on regular mode. Plus, when the jumper is removed, the timing still sits at 0 Degrees. It does advance to about 12 degrees when I am at about 2500 RPM. When at WOT I can't see the mark as I don't have an advance timing light.
I do believe that something is not right. The ignition EST module is brand new.
Ideas anyone?

What is the total supposed to be ?

Why was carb rebuilt and ign module replaced ?

I too rebuilt a carb and replaced module on a 3.0 the other year.so i remember some things..but it was a Volvo Penta so has the luxury of having a Holley 2bbl. :)

total should be 24 Degrees. I honestly don't think it's even close. Curve shows minimum at idle should be 12 plus or minus 2. I show 0 no matter what at idle.

The carb was rebuilt because the boat sat for 7 years before it was given to me. I changed all ignition components too because I could not confirm what worked and what didn't plus age. The distributor is the same but the pickup coil and rotor and cap is all new. The carb is good now as it starts and idles and performs otherwise perfectly. The jets are all clean and working perfectly and tested with a manual pump to ensure flow. The problem solely rides with the timing at this point. It just isn't doing what the book says it should do. Could it be yet another failed EST module? This is the third one. Original, then new one didn't even give me ignition and then this third new one is acting weird I think.

Okay thanks. I set things to total,,,don't give a damn to initial and i don;t have to set things at idle to make the EST go into base timing mode and etc.

I rev engine until the advance stops advancing and rev it a little higher to make sure,,,and then set total to that rpm,

I do have in my notes what AcDelco Module I installed in that EST distributor if you need that to compare ?

I can't set to total anyway because I don't have an advance timing light. Please let me know the module number? I got the last two from the local auto parts dealer who sells West Marine parts so it should be correct in both cases. I just think it's faulty is all I could see.

Found it. Got it thru Amazon as I get most of my ACDelco parts thru there. I buy tons of AcDelco parts. :)

This one:
ACDelco D1965A GM Original Equipment Ignition Control Module
by ACDelco
Link: http://a.co/fGn9aJv

BTW: Do you know how to apply and what heat transfer paste to use with modules ?

I use an advance gun always and I set engines to total always. I'm 321 yrs old....I had a pet dinosaur. This works :)

this is exactly what I got. The paste I used was in the box. I like to use the same paste that I use on CPU's. It is designed to be the best heat transfer.

How do you know your boat is 10mph slower than it should be if it hasn't run right since you've had it ?

Funny!

Because it is a very common boat and there are loads of people online who clearly said it should get at least 40mph. I saw videos too showing different exact same boats performing (including seeing the rpm range and speedo) and clearly I am missing. All within roughly the same range that I am not getting. I am missing rpms plus speed.

I honestly don't even care if I get my current 30 mph vs 40mph, I just want to ensure I am not damaging the engine at the lower rpms. I only get 3900 to 4000 rpm. The WOT for this engine is 4600-4800. Is this an issue with how it is running? Also, I want to ensure that I have enough get up and go to get out of the hole easily pulling people out of the water.

Make sure the gear ratio in the outdrive is correct and the prop is correct.

Back to timing: althouh I have never done it, do you follow merc's timing procedure for the 3.0 ?
http://www.boatfix.com/merc/bullet/90/90_15.pdf
Did you also do #3 ith shift interupter ?

I had the proper prop on it that would give me that high top end if I had the RPM's. Then I changed to a specialized 4 blade vented aluminum to give me the hole shot but still not enough rpm.
I do follow exact procedures but when i take it off base mode, it still doesn't advance to the required 12 +- 2degrees at idle. It just stays at 0.

I do know the advance jumped to full advance very quickly off idle. Maybe your idle is a bit high, at full advance, which you set at 0*.

I've seen stranger schit !

Beg or borroq a total timing light or install timing tape for the balancer.

Sorry for weird typos. Lying on couch ith lights off, other than TV, I need one of hose lighted keyboard deals,. :)

the 3.0 marine engine from the 90 s to early 2000 s had issues with the cam gear keyway slot wollowing out. Especially in the 90 s ----- and your engine serial number is from 90 s.

I have not read any of the posts except the header.

Merc had 2 different ignition set ups in the 90 s for the 3.0 L -- are YOU SURE YOU HAVE EST IGNITION SET UP HERE ? Just asking.

There is a Service bulletin on timing should be thru Merc and Volvo has one as well. It might be 1 ATDC if I recall. I would have to look it up.

Well I was CORRECT about the 1 ATDC --- man I still have a really good memory. But the service bulletin list does not fall under your serial number. If recall correctly --- I think possible we even back dated / back serial number with the 3.0 L to the 1 ATDC so the owner did not have detonation issues with the newer gas blends at the pump. E 10 is a leaner mixture fuel was my point back then. We had E 10 for a long time in the area and before that M 5 fuels.

I would have to run your engine serial number to remember or look at the which service manual covers your 3.0 L Merc to be 100 percent sure about the timing Anyways the Service bulletin for a couple years later than yours is in the link below.

http://www.boatfix.com/merc/bullet/98/98_14.PDF

Doesn’t leave base timing mode
 

So, you are getting around 12-13* advance from the module.
Do some searching, but I don't think these modules have 23-24 degrees in them.

OK I get it, you don't want to spend $100 on a critical tool that insures your boat performs correctly and does not blow up. Try this. If at 2500/3000 RPM you are getting 12 deg advance measure the distance on the harmonic balancer from 0 to 12 deg. Double that measurement and make a mark on the balancer, now you have a 24 deg mark. Spin the motor to 3000/3500 RPM and see where your 24 deg mark is. Cheap, easy not real accurate but not terrible either. Good luck

If you need just set the total to the 24 mark @ 3500 RPM by adjusting the distributor at 3500 RPM. Check the base at idle and I bet it reads about 10-12 deg.
Am I missing something.
Disclaimer: I run a T-Bolt ignition and carb set-up. 34 deg all in base about 10.

BTW: Many sources say to apply the + wire for the timing bypass'wire' set up when engine is running only/ May damage module they say.
Where is one of many sources that mention this:
https://forums.iboats.com/forum/engi...ming-procedure

Again. I just set total, therefore I don't have to use such methods :)

I'm wrong and should have remembered, module provides 22-23* advance - but comes in ultra fast from 600rpm or so:
Curve and etc is in here:
http://www.boatfix.com/merc/Techbk/95/95HGB4.PDF

EST? Small cap HEI with Delco Voyager module? Module is only good for about 12° advance. It is really a pass car module that has some centrif advance built in to limp mode. You could have another chip that has no advance built into limp mode.

Ok, in a 4cyl you get about 24 degrees. Doable.

first and foremost have to say about the Merc --- this is not a Volvo set up so do not use the Volvo info. the info about this is --- for one Merc uses a shift interupt switch VOLVO DOES NOT. With Merc for this EST --- you have to bypass the shift interupt when checking timing and or setting timing. With that said -- you unplug the shift interupt and plug leads together using a connector wire with bullet connectors. Have no idea if this has been mentioned or not plus nor do I want to read all thru the replies posted. Sorry about that one

Timing lite properly connected -- fully warmed engine -- idle speed 600 rpms install jumper wire between the 2 white leads on the distributor. Next is to by pass the shift interuptor switch. verify that timing does advance to - initial timing 1 BTDC advancing to 12 BTDC + or - 2 degrees next is at 2400 - 2800 rpms --- max total advance should be 23 BTDC + or - 2 degrees.

There you go hope this helps whomever fully the correct OEM info and procedures here . Good luck.

. And again the cam gear is very bad about wollowing out the keyway slot JUST some added info and FYI as well.

Kent Moore sells an EST module tester for anyone interested.

forgot to add the timing chain gets worn out here as well - 400 to 500 hours these engines need alot of attention internally. They also corrode from the outside in very easily from any salt air content

I replied on your post about that like 4 years or 5 years ago. I thought your issue was the batteries were bad - weak cells / low voltage at the batteries ?

^^^^^^^ I did remember it 4 or 5 years ago - . You are correct not a battery issue. Anyways I found the post and some good info for T bolt V for whomever.

the 3.0 L marine engine does not have a Knock sensor nor T bolt ignition. Carry on.

https://www.offshoreonly.com/forums/...ion-issue.html

Just got worse!
 

You have a BADDDDDDD pick up coil in the distributor. It finally went out completely would be a good guess. Prob been your issue for a while

Also do you know that your mechanical fuel pump has a filter in the bottom cover portion ? And the more the boat sits the worse the filter gets. It needs to be changed once per year regardless if the boat sits or runs. Regardless as it really needs to be changed once per year

number 2 in the parts diagram in the link below. At first until 1998 the filters were ceramic filters inwhich come apart and clog alot of the fuel system up.

Merc went to the paper element filter and as a replacement but the paper comes apart as well when not changed soon enough. Have no idea if you know this or not but passing it on for the taking.

You should have fine nesh fuel filter in the inlet carb fitting as well -- that needs to be changed out once per year as well.

And for the record the cam gear keyway wollow out --- the start of it is around the 200 hour mark. Does nt matter how pristene the engine is. It is a cheap soft gear. These engines were in a 1976 thru 1980 chevy chevette back in the day and not used in an auto since 1982.

MerCruiser 3.0LX GM 181 I / L4 1990-1995 Fuel Pump & Carburetor Parts