timing not advancing, unique issue, ideas please

[turbocorrado]

so my boat is a 97 wellcraft eclipse, 4.3 v6, my timing isnt advancing past 23 degrees. the ignition is a stupid hybrid year. the distributor doesnt have counter weights, it doesnt have knock sensors. it has an ecu thats supposed to advance timing. i have the purple/white grounding wire to set timing. last season the boat felt like it had no balls and wouldnt rev past 3600, when we timed it last year we didnt ground the wire to do "base timing" tonight i tried doing it and im only getting 23 degrees at 2500 rpm, we have base timing set at 10 degrees

relevant info:
~PO told me he sunk the boat twice, and he never ran it after the last time it sunk - he waited till after it was in my name to tell me this, i bought it in july of 2014
~i ran it for 2 months the way i bought it. it would never rev past 3700, if i floored it with the trim down it would go about 3300rpm at 32mph, when i trimmed up i could get 3700rpm and 37mph out of it.
~i rebuilt the motor in feb of 2015 after finding that the motor had 2 cylinders with 90 psi, we set timing to 10 degrees without grounding out the purple/white connector. i ran it all of 2015 like that, it would rev to 3600 no matter where it was trimmed and topped out at 36-37mph

 

[NHGuy]

So ground the wire and time it. Then let us know if it's still not good.

 

[turbocorrado]

So ground the wire and time it. Then let us know if it's still not good.

i did that tonight. set base to 10 degrees, getting 24 degrees at 2500 rpm. i was expecting to get in the low 30's

 

[turbocorrado]

No Title

the motor was replaced in 2006 everything i find says a 4.3 should be set to 8 degrees and only has 14 degrees advance, which seems low. my flame arrestor says 10 degrees and special timing required, im only getting 3700rpm, it says 44-4800

 

[jimmbo]

When you rebuilt it, did you replace the camshaft? Have you done a compression test lately? Is it a 2bbl carb, or a 4bbl?

 

[Bondo]

i have the purple/white grounding wire to set timing. and im only getting 23 degrees at 2500 rpm,

Ayuh,.... Did you take it back out of base timin' mode,..??

If it's never rev'ed to the proper rpms,.... What pitch prop is on it,..?? might be too big,...

 

[flipbro]

With it being sunk twice I would weight it. You may also have a water loge hull contributing to the problem of low rpms..

 

[turbocorrado]

When you rebuilt it, did you replace the camshaft? Have you done a compression test lately? Is it a 2bbl carb, or a 4bbl?

i re-used the original camshaft, motor was bored .30 over, havent done a compression check lately and its a 2bbl

 

[turbocorrado]

Ayuh,.... Did you take it back out of base timin' mode,..??

If it's never rev'ed to the proper rpms,.... What pitch prop is on it,..?? might be too big,...

we took it out of base timing mode and tested the max advance
its a brand new prop as of last season and its a 14.5x21 iirc

whats confusing me is im of the understanding base timing mode is just eliminating the knock sensors from the picture, but my engine doesnt have knock sensors so what is the purple/white wire supposed to do

 

[alldodge]

With timing at 10 BTDC means you have the TB-V module. The TB-V module provides 10 to 15 degrees (depends on module) of timing advance from base timing, and IMO your module is working correctly.

Base timing mode does not eliminate the knock sensor, it keeps the motor at zero advance during the timing process.


Under normal circumstances a 21 pitch prop should be getting you closer to the 44-4800 rpm, right now you have to much prop. Since the boat was sunk twice, my guess would be you have a different drive ratio then what came with the boat. Your going to need to get to about a 17 pitch prop.

So far your boat appears to be running correctly and the TB-V is working.

 

[turbocorrado]

With timing at 10 BTDC means you have the TB-V module. The TB-V module provides 10 to 15 degrees (depends on module) of timing advance from base timing, and IMO your module is working correctly.

Base timing mode does not eliminate the knock sensor, it keeps the motor at zero advance during the timing process.


Under normal circumstances a 21 pitch prop should be getting you closer to the 44-4800 rpm, right now you have to much prop. Since the boat was sunk twice, my guess would be you have a different drive ratio then what came with the boat. Your going to need to get to about a 17 pitch prop.

So far your boat appears to be running correctly and the TB-V is working.

thanks alot for the help, im pretty sure i know of a marina that lets you play with props so il get in contact with them

also in my scouring the web i came across a guy who had a similar problem - lacking power, not revving out, and not hitting top speed. he said his engine was running smooth and it turned out one cylinder wasnt getting spark, so il pull all my plugs tonight and just double check that just to be safe

 

[FreeBeeTony]

I think the question is: is the OP getting 25* of total advance or 25 + 10 = 35*?
Or am I misunderstanding the TB-V ignition set-up?

 

[turbocorrado]

.

in reading that chart in the mbt section, about 1/3 of the time if i punch the throttle and the boat nosed up hard the alarm would go off, i always assumed it was a bad sensor in the gear oil reservoir, i wonder if the alarm going off is shutting things down as well

 

[turbocorrado]

im only getting ~24 degrees total advance, but the v6 is supposedly only supposed to at 14 degrees so theoretically the 24 is correct

 

[FreeBeeTony]

OK.........I'm comparing it to a V8........my error.

 

[turbocorrado]

OK.........I'm comparing it to a V8........my error.

yea i was doing that until yesterday afternoon i just assumed since its pretty much the same thing minus 2 cylinders that the timing would be the same as well

 

[alldodge]

in reading that chart in the mbt section, about 1/3 of the time if i punch the throttle and the boat nosed up hard the alarm would go off, i always assumed it was a bad sensor in the gear oil reservoir, i wonder if the alarm going off is shutting things down as well

There are three things that can cause your alarm to go off, engine to hot, drive lube low and oil pressure low. Any time an alarm goes off you should really look into that.

The alarm is just 3 switches and they only turn the alarm on, they have no effect on anything else for your motor.

 

[alldodge]

The timing advance is the same give or take one degree for the TB-V. The word advance is where the misunderstanding happens. The advance is more Before TDC, not After

8+15= 23 degrees advance BTDC
10+14= 24 degrees advance BTDC

 

[turbocorrado]

There are three things that can cause your alarm to go off, engine to hot, drive lube low and oil pressure low. Any time an alarm goes off you should really look into that.

The alarm is just 3 switches and they only turn the alarm on, they have no effect on anything else for your motor.

i know oil pressure and temp were good i was watching them on the dash. gotta be the gear oil

 

[turbocorrado]

The timing advance is the same give or take one degree for the TB-V. The word advance is where the misunderstanding happens. The advance is more Before TDC, not After

8+15= 23 degrees advance BTDC
10+14= 24 degrees advance BTDC

yeah i know, im kinda wondering if im getting the added acceleration spark advance on top of the base timing setup. im splashing the boat sunday i hope so il be able to give it a good shakedown and try some stuff