Mercruiser question

[stvhelm]

I'm working on a 1995 mercruiser 5.0 engine with a 2 barrel carb.
what should the timing be set at at idle speed? and what should it advance to at 4500rpms? engines just seems sluggish.
The compression is all good. all the plugs cap, rotor and wires been changed 2x. The carbs been gone through several times. fuel pressure is ok. Im thinking the distributor is not advancing enough. it does advance a little you can see it with the timing light at idle if you rev it up but im not sure about when its under way. right now at idle this motor is at 10-12 degrees btdc. is it common for the distributor to hang up and only work half way? Im not far from bringing a large hammer on board

[THEFERMANATOR]

IIRC a 95 MERCRUISER is an all electronic advance set-up through a black box mounted on one of the risers. I have an 88 that is set-up that way with no advance mechanism inside the distributor. I know they normally have a few of the timing modules for the late models on EBAY pretty consistently. I know MOST of them are set to 10 at a 600-750 idle speed IIRC, and should advance to up around 28-32 at 4000.

[stvhelm]

so youre saying no timing advance is done inside the distributor? thats a good thing cause the back half of these engines are hardly accessible.

[Capt.Insane-o]

It's all done with the module. which may or may not be mounted on the distributor. ;) The module is either on the riser or on a bracket on the back side of the distributor. If the sensor under the rotor has never been changed now is as good of time as any too.

[Drewsmarine]

Setting timing depends if you have a Thunderbolt IV, or a Thunderbolt V ignition system. Your engine could have either. If it is a Thunderbolt IV, timing at idle is 8deg. BTDC and should advance 22deg to a total of approximately 30 deg.
If your ignition system is a Thunderbolt V, timing is electronically controlled. Base timing is adjustable (to 10 deg.) by using a jumper wire and connecting the ignition system timing lead (purple/white) to ground. This puts the system into base timing mode. And adjustments to base tming can be made by turning the distributor. When running the eng. the electroically controlled ignition is very suttle. With no load on the eng, you will not see much advance in timing.

[stvhelm]

Is there a way to test the advance module? do you have a part number for it? maybe i'll just swap it over from the other engine.

[Tom D.]

Is there a way to test the advance module? do you have a part number for it? maybe i'll just swap it over from the other engine.

Timing light while underway is probibly the only way to test it.

Tom

[mirage243]

Setting timing depends if you have a Thunderbolt IV, or a Thunderbolt V ignition system. Your engine could have either. If it is a Thunderbolt IV, timing at idle is 8deg. BTDC and should advance 22deg to a total of approximately 30 deg.
If your ignition system is a Thunderbolt V, timing is electronically controlled. Base timing is adjustable (to 10 deg.) by using a jumper wire and connecting the ignition system timing lead (purple/white) to ground. This puts the system into base timing mode. And adjustments to base tming can be made by turning the distributor. When running the eng. the electroically controlled ignition is very suttle. With no load on the eng, you will not see much advance in timing.
He is exactly right, good post.

[stvhelm]

no module on the riser. its on the distributor, is this thunderbolt IV or V. Are there any weights in this distributor that can be stuck? I would look myself but I can even get close to it. I dont know how Im even going to get the module off it to change it.

[mrcrsr]

no, its fully electronic, the advance is done by the module, get me the model number/serial number and i'll look it up for you, you can also bring the motor up to 3000 rpm, even in neutral, and you should see the timing has at least 32 deg. btdc, you'll need to use a timing lite w/ adjustable advance,some of these engines also required you to ground one of the pins on the module to set timing

[stvhelm]

thanks for the info
also now, does anyone have this crank balancer aluminum drive pulley?

http://i32.tinypic.com/2d10ghs.jpg

[mirage243]

thanks for the info
also now, does anyone have this crank balancer aluminum drive pulley?

http://i32.tinypic.com/2d10ghs.jpgI probably do but need more info, year, cid, etc. let me know.

[stvhelm]

I probably do but need more info, year, cid, etc. let me know.

for the engine in my first post 1995 5.0L mercruiser 305ci. I need the long screws for it too. the steel pulley screws are too short.

[mirage243]

I'll check and let you know. Sorry, I didn't go back and read the post.