Degrees timing

[Sashap]

1992 mercruiser 3.0 serial D706324.
What is correct timing at idle? Mine is 0 degrees right now. Would 1 degree Btdc make a difference? If so, how? Everything else is smooth but could use touch more power. I know about prop, weight, etc. Just this question on timing please.

 

[Scott Danforth]

Set it per manual.

If you want more power....get a bigger motor

 

[Sashap]

Set it per Manual

Seriously? Why bother posting? If I had a manual I wouldn’t be on here.

 

[Bt Doctur]

your not going to get that much more performance bumping up the timing and may blow the head gasket if you try.

 

[Sashap]

your not going to get that much more performance bumping up the timing and may blow the head gasket if you try.

Thanks. Not really trying for a lot of anything. More to the point, I am ensuring that it is exactly as should be. I noticed today that it is at 0BTDC. I found so much conflicting information on the actual degrees. If I set it to 1BTDC would it effect anything? Would it make it just a bit better? Or?

 

[Sashap]

I am leery about how the timing is working quite frankly. I set it according to the method with the jumper/shift interrupt, but it just doesn't sound different when the jumper is set etc. It does show it advanced at about 12 degrees when at about 2400 rpm, but it still shows 0 degrees at idle with the jumper off. I can accelerate in the water, get on plane and cruise, but the top speed seems low by 10 mph. I honestly think it can do better as I have seen videos of the exact same boat doing much better. There is so little foam in this boat too. About 8 inches wide by 8 feet long strips times 2. The foam isn't wet either, I checked.
Something sounds weird about the timing.
That all being said, it starts with half a turn usually and sounds great, both quiet and smooth.
Is the timing weird or what?

 

[Sashap]

Also, compression is good. Don't remember the exact numbers as it was done over a month ago, but all were equal give or take 5lbs too.

 

[Sashap]

I am running with EST ignition (all new).

 

[harringtondav]

Sashap , I feel your pain. But it depends on which Thunderbolt Ignition module you have. FYI my '96 4.3 LX has Thunderbolt IV, with a base timing of 8 deg. BTDC with a 22 deg. max advance at 2500 rpm. Don't try this at home, this is just an example. Hopefully someone with your engine manual will chime in, and give you your base timing spec.

 

[Bt Doctur]

 

[Sashap]

I have the AC Delco EST. So, it's clearly 1 D BTDC.
The one degree difference from my actual 0 Degree shouldn't make this kind of difference should it?
Could this module be bad too? It just doesn't change after I take it (supposedly) off base timing mode.

 

[Scott Danforth]

There are multiple threads about the 3.0 where people advanced timing thinking they would get more power only to cause detonation.... damage pistons and spit out head gaskets.

The 3.0 isnt a performance motor. Its a forklift motor that is also being sold in base model boats

If you suspect the ignition has issues, follow the troubleshooting guide in the stickies

If your low on WOT, look at the fuel system. There is an entire sticky in low WOT troubleshooting

 

[Sashap]

i verified that timing in base is 1 btdc. Idle at 500 rpm.
When I removed the shift wires then removed jumper nothing changed. At 2500 rpm timing show about 12 btdc.
I tried several times and seems to stay in base. I can get about 3900-4000 rpm max on water.

 

[Scott Danforth]

12 BTDC at 2500 sounds a bit low for a 3.0. with the voyager dizzy, it should be about 20 degrees by about 2000 RPM and all in at 23 degrees at about 3000 RPM

http://162.144.28.33/lib/mercruiser/manuals/mercruiser13.html#/194

is this a new issue or has it always been that way?

follow the troubleshooting in the manual

 

[Sashap]

12 BTDC at 2500 sounds a bit low for a 3.0. with the voyager dizzy, it should be about 20 degrees by about 2000 RPM and all in at 23 degrees at about 3000 RPM

http://162.144.28.33/lib/mercruiser/manuals/mercruiser13.html#/194

is this a new issue or has it always been that way?

follow the troubleshooting in the manual

It has been this way since I got the boat and started to get it ready after 7 years sitting. I don't have an advance light and no way to get one where I am at. Someone said to set at 24 BTDC at 3500 RPM instead and that should be good. I'm kind of leery about doing that. Is this safe? It just doesn't go out of base mode as far as I can see. It starts great, idles great and planes up with both props (although the recommended 19 is a bit slower on the hole shot). However, in both cases, there is not the full 4600 rpm. I know it's the timing issue.
Can I safely try the above method or am I crazy to think it's safe? My worry is that it might be stuck in base and I have no real way of confirming if I am doing damage.

 

[Scott Danforth]

could be fuel issue.
could be a timing issue
get timing tape for the damper. no need for an advancing timing light

19P was the max I could run on my 3.0, most of the time I had a 17p on the boat or a 15p for water sports and trolling.

if it doesnt advance, you're not doing any damage. most damage is caused by that little motor being too far advanced.

 

[Andy J]

1992 mercruiser 3.0 serial D706324.
What is correct timing at idle? Mine is 0 degrees right now. Would 1 degree Btdc make a difference? If so, how? Everything else is smooth but could use touch more power. I know about prop, weight, etc. Just this question on timing please.

My manual says 0 degrees on 87 octane gas, changes for 89. I run non-ethanol 87 gas and mine runs fine on 0 degrees.

Advance it too much and you can cause engine knock

 

[Sashap]

It just got worse. Took the kids out tubing. Out of hole took a bit of time, but at a certain point (didn’t watch when) it suddenly picked up and then went ok. Pulling a tube with two kids still got 4100 rpm. Satisfactory for that at least. Four starts later it stalled and couldn’t get it started at all. Zero spark. Picked up a new coil and still no start.

plugs all new, wires tested ok on ohmmeter, pickup coil 850 ohms, tried my spare est module, safety lanyard ok. Don’t know what else to try!
help?

 

[Sashap]

Fixed. Loose wire on ignition switch

 

[Sashap]

I spoke with a marine mechanic and he said that the module is working. What is not working at this point is that it is stuck in base mode. I have followed the procedures over and over again and cannot leave base mode. I have unfortunately both of my available modules both stuck in base mode. Is there any way to reset them? The timing in base is absolutely correct. It just does not leave base mode. How can I tell? It stays at 1DBTDC. Only advances to about 12Degrees at 3000 rpm. I am clearly missing 1000 rpm at WOT and rpms struggle until about 2400 rpm under load at which point it goes but only to a max of 4000 rpm with a reduced pitch prop. With the stock prop, it only goes to about 3500 rpm max. With engine running, put shift interrupt switch back to normal, then removed jumper at distributor. Did this countless times as per manual.
Checked voltage at jumper and it is 12V+.
Ideas? No sense saying I am overpropped, carb etc. This is clearly a timing issue and solely to do with lack of advance.
It never leaves 1DBTDC at idle.
It should read 12DBTDC at idle when not in base mode.
Someone suggested to set it at WOT to whatever the advance is, but that is not good because it still doesn't have the proper advance curve.
Buying yet another module might be an option but I just feel that there must be a way to set the ones I have back to regular timing mode.