duunoit

Vmax, I hope you don't mind... It looks like we already have all the people in the know about this stuff right here so I won't start another thread. I just put a B&M 174 on my HP425. I bought a V6 module and am wondering where I should set my initial timing? Thanks for the help...

Chris

HiPerf2000

dont worry yourself about the initial base timing. Just set your advance somewhere below 32 (mine is at 28 to be safe), and let the base timing fall whereever it lands. the V-6 has 14 total advance, so the base should land around 14 - 18.

Griff

The V6 module gives 6-10* of advance on a V8 engine. If you're looking for 30 total, then set it 20* and go up from there.

Vmax

hi-perf-2000,
I would like to take one of your used V-6 modules off your hands if still interested. Leave me some contact info a email or phone number.

Vmax

HiPerf2000

Vmax.....

send me an email [email protected]

Mark

RLW

Griff,
If he is going to use the V-6 module, shouldn't he set the timing for 30 degrees at say, 3200-3500 rpm and let the initial timing fall where it may. That way he is not running to much advance timing.
Like I said before, I run 29 degrees locked as per the recommendations of my blower guy. Conservative I'm sure but cuts down on the chance of having lots of little aluminum pieces lying around.

Griff

Yes, I agree that that is the best way to set it after you get the initial in the ball park. He can set initial at a low/idle rpm on the initial start up to about 20*, then let the engine warm up. When it gets up to operating temp, then he can fine tune total timing and carb adjustments.

Vmax

Just wanted to close out his thread with information to document what fixed my idle problem. As many had recommended issue was not enough initial timing to let my 454 blower motor idle smoothly. Resolved issue using V-6 ignition module with the 12 degrees of advance. I'd did not use the variable advance timing light to set final advance timing but instead purchased a timing tape and installed it on the harmonic balancer and aligned advance timing to 0 deg. pointer. Saved investing in a 70 dollar timing light. Found my advance timing at 3200 RPM was running 28 degrees with the V-8 module so that is where I set advance with the V-6 module 28 degrees for now. I then adjusted the two idle mixture screws on the HP 500 800 CFM carb to give me max RPM and vacuum with the boat in the water in gear and prop turning backed idle stop screw out for this also. Leaving boat fastened to trailer with tie downs still on backed in the water worked great for this. End result boat purrs like a kitten at 700 RPM no need for idle stop. Dropping into gear she turns the 27P mirage at 650 RPM no stalling no loading up. Cold starts are not the belching revving experience and it also no longer floods out occasionally trying to get the motor running after it is warm. Thanks to all OSO members who provided constructive inputs. I also found out that my HP 500 carb was set up with boost referencing and I'd did not know it by my buddy who installed it. He took care of the horsepower end just not the around the dock livability. Boost Reference is definitely way to go for clean running, response, and mileage.

If any body needs a Merc V-8 ignition module with 24 degrees advance let me know. I also have the Holley Carb I removed available. It needs a rebuild but it is a nice looking carb with no choke horn Holley HP style. I believe it is a 830 or 850 not sure how to tell. Is automotive without J tubes or stepped throttle shafts so could run as is in open bilge or retrofit. I think it was a not manifold referenced supercharger carb from Holley the photos match up.

Griff

Glad it all worked out for you. You might want to experiment with bumping the timing up a few degrees. Run back to back tests in the same water/conditions. See if you gain any rpms on the top end by advancing it a couple more degrees. You should be fine up to 30*or 32*. If you don't pick up any rpms on top, then just move it back to the 28*.

puder

one thing i'd HIGHLY recommend is to loose those stock merc manifolds those things leak like mad and flow like ****....

yoursetup is very similar to mine. I;m running the same blower and heads but i have 1050 dominator carb and stellings headers.

Make sure you upgrade your fuel pump. 5psi at wot is low. YOu might also htink abou abigger oil cooler. Stock merc ones are kind of little and i had heat issues prior to adding the big eddie marine oil cooler.

ALos and msd ignition box with a blaster coil might not be a bad idea. Pretty easy to hookup to your tbolt ignition as well.