Thunderbolt V timing

[supervised treatment]

hello
i have replaced the 5.0 in my boat with a 5.7 i wanted to use the wire harness that came with the 5.0 and the thunderbolt V system. last year the when i installed it the icm wouldn?t advance as the rpms rise. I decided without trouble shooting it to replace the ignition with an aftermarket msd distributor. boat ran great until the last trip of the year when the ignition failed. I sent it back and they confirmed that it was bad and they rebuilt it. this year I tried the thunder bolt V again. it appears to advance but not as much as the advance curve graft from mercruiser. The boat runs good but dogs upon a hard acceleration

so my questions are without a load on the motor will the distributor-* advance as showed in the graph and is there any way to test the icm I?m also wondering if the icm for the 5.0 work with the 5.7

 

[Bondo]

The boat runs good but dogs upon a hard acceleration

Ayuh,.... Welcome Aboard,...... That sounds like fuel delivery,.... Induction,....

Is this carbed,..?? Efi,..?? Mpi,..??

The 350 should run fine with the 5.0l module,...

 

[alldodge]

I need more info

What MSD distributor did you use (part or model number, something)?
What model TBV do you have?
What base timing are you setting the motor at?

 

[supervised treatment]

the 350 has a quadrajet on it and the 305 had a 2 barrel . the [h=1]MSD Ignition Distributor, Chevy V8 Marine, Ready to Run[/h]

Part No. 83606 had to be set up with the lightest springs for the quickest advance and it worked great last year the tbV from the 305 is a 861459-1 and i have a used 861254-1 im going to try next . i just not sure if without a load on the motor will it advance like the graph of the advance curve ive got the base timing set at 10 degrees before top dead center

 

[supervised treatment]

oh yea the icm does not have a knock mod

 

[supervised treatment]

No Title

 

[alldodge]

Sorry, but all I'm getting out of info requested is: the thing a magig was over there and was set by Billy Bob

The one thing that has info is the ECM does not have a knock module

 

[CaptainMak]

So you have an advancing timing light and know how to use it I presume? The CARB models are 10? BTDC. Is it ? If not, you'll have to follow a procedure to set it correctly. You can't just do it in idle.

Then go from there. Take measurements at 1500rpm, 2000rpm, 2500rpm and follow the graph you posted. It should be advancing close to the chart. BTW, at over 2k RPM, you'd probably want the boat in the water, not on a hose.

 

[supervised treatment]

i dont have a advance timing light
i have been watching the timing while someone works the controls
if you rev it to 1500rpms it will go to 18 the fall off to 15
im thinking it could be the MBT mode adjusting the timing
the graft shows advance of 15 +the base timing

 

[alldodge]

The TBV has to be put in base timing mode to set. If you have a MSD box, I don't know. To put in base timing for TBV you ground the Purple/White wire and the set timing

 

[achris]

the 350 has a quadrajet on it and the 305 had a 2 barrel . the [h=1]MSD Ignition Distributor, Chevy V8 Marine, Ready to Run[/h]

Part No. 83606 had to be set up with the lightest springs for the quickest advance and it worked great last year the tbV from the 305 is a 861459-1 and i have a used 861254-1 im going to try next . i just not sure if without a load on the motor will it advance like the graph of the advance curve ive got the base timing set at 10 degrees before top dead center

You can't use a TB-V (or IV for that matter) with a distributor that has advance weights and springs. Pick one, TB-V OR weights and springs.... Not both.

 

[supervised treatment]

yes i grounded the test leed to base time and the msd that im not using didnt have a box

 

[supervised treatment]

the msd had weights but im not using it i have the TBV distributor and the TBV icm

 

[CaptainMak]

yes i grounded the test leed to base time and the msd that im not using didnt have a box

So where are you at in base timing mode? If you don't have the right tools like a timing light, really hard to troubleshoot timing

 

[supervised treatment]

yes im using a timing light
set base timing at 10 degrees before top dead center

 

[CaptainMak]

Are there any active codes that you're aware of ? That's when an ECU might throw itself into a derate mode.

Can you give us the readings at various RPM's ?

 

[supervised treatment]

It?s a 2000 it only has a icm ignition control module
there is no computer that stores codes