Timing check 350 5.7l Carb

[wryork25]

I saw a thread that made me confused and I am hoping to get some clarity. I was under the assumption that when checking the timing you were to ground the purple and white wire to get the ignition into base timing. The thread that I was reading said that you jump it to positive 12 volts? Is this correct or do I jump it to ground like I originally thought.

 

[Bondo]

Ayuh,...... Welcome Aboard,...... Is this the T-bolt IV ignition, or T-bolt V ignition,..??

Post the motor serial number if you don't know which ignition,...

 

[wryork25]

I am not currently at home to check serial number but I believe it is a T-bolt IV. The ECM is mounted to the dizzy and it only has one plug, and I do not have knock sensors.

 

[Bondo]

I am not currently at home to check serial number but I believe it is a T-bolt IV. The ECM is mounted to the dizzy and it only has one plug, and I do not have knock sensors.

Ayuh,...... No wires to mess with, with the T-bolt IV,....
Just point, 'n shoot with yer timing light,......

 

[wryork25]

I will check the serial number and get back with you. Now I am not sure because I have the shorting purple and white with a bullet fitting on the starboard side of my engine between the carb and manifold. This is one if the locations of a few that I read where this can be located. I assumed that it was where I connected to short to ground. Is there a version of the T-bolt V that only has one plug on the module? From what I read and pics I saw, they have two plug connections.

 

[Bondo]

The ECM is mounted to the dizzy and it only has one plug,

Ayuh,..... There should be printing on that module that says T-bolt IV,.....

 

[Scott Danforth]

TB IV uses a timing light and you set the motor to 6-8 degrees per the manual for your motor. No different than any generic distributor. No base timing mode. Just must be set at idle.

TB V needs to be put in base timing mode by grounding the purple/white wire, then adjust to what the manual states for your motor.

 

[Scott06]

I will check the serial number and get back with you. Now I am not sure because I have the shorting purple and white with a bullet fitting on the starboard side of my engine between the carb and manifold. This is one if the locations of a few that I read where this can be located. I assumed that it was where I connected to short to ground. Is there a version of the T-bolt V that only has one plug on the module? From what I read and pics I saw, they have two plug connections.

Take a picture of the module and post if if you have the wire on the ma I fold with a black rubber plug in it you have the T bolt 5 .

what year is the boat?
yes early versions of the t bolt 5 had a module mounted on dist with an oblong wire harness connection. Later ones had it mounted on exhaust elbow and had two square smaller plugs to connect to module.

assuming it a 5 just ground the purple white wire. You can see this with a timing light as the timing will not move at idle and should be around 10 btdc. When it is not in base mode the timing should move at idle and advance when throttled up. I’ll see if if can find a pic if the page in the manual. If you’re going do a lot of work get the factory manual for your engine it has all the various versions of ignition fuel and other systems and will tell you exactly what you need to do.

why are you checking the timing is there an issue ? Typically with electronic ignition it doesn’t move.

 

[Scott06]

Here are some snips from the manual that me help you
They may be out of order when I hit the screen shots page numbers are in lower left. The pic of the early TBV module with single connector may help u match up what you have .

 

[Happygolucky]

sounds like "TB V" without knock sensor !) Yes ground the purple/white wire to stop the "TB V "from adjusting timing while you set the base-timing by turning the distributor .

 

[wryork25]

Here are some snips from the manual that me help you
They may be out of order when I hit the screen shots page numbers are in lower left. The pic of the early TBV module with single connector may help u match up what you have .

Scott, Thank you for the information! At first glance this should be very useful, the next chance I can get to look at it... Youth Baseball Season...

 

[wryork25]

sounds like "TB V" without knock sensor !) Yes ground the purple/white wire to stop the "TB V "from adjusting timing while you set the base-timing by turning the distributor .
View attachment 406142

You answered my next question, so there are versions without the knock sensor?

 

[wryork25]

Take a picture of the module and post if if you have the wire on the ma I fold with a black rubber plug in it you have the T bolt 5 .

what year is the boat?
yes early versions of the t bolt 5 had a module mounted on dist with an oblong wire harness connection. Later ones had it mounted on exhaust elbow and had two square smaller plugs to connect to module.

assuming it a 5 just ground the purple white wire. You can see this with a timing light as the timing will not move at idle and should be around 10 btdc. When it is not in base mode the timing should move at idle and advance when throttled up. I’ll see if if can find a pic if the page in the manual. If you’re going do a lot of work get the factory manual for your engine it has all the various versions of ignition fuel and other systems and will tell you exactly what you need to do.

why are you checking the timing is there an issue ? Typically with electronic ignition it doesn’t move.

Without getting to far in the weeds my carb was dumping fuel and very poorly running. I rebuilt the carb and when I was reinstalling it had my hand on the dizzy. when I went to get up the dizzy rotated some. I moved back approximately how much it turned but not exact. The clamp was not very tight.
I have not used the boat very much in the last two years because of family obligations, I am trying to get it right in hopes of using it more. I never had to adjust timing in the past it has never been an issue. Thank you for the help!

 

[Scott06]

You answered my next question, so there are versions without the knock sensor?

yes some engines had no knock sensor. TB4 had no knock sensor at all. TB5 some engines have a knock sensor some do not.

Without getting to far in the weeds my carb was dumping fuel and very poorly running. I rebuilt the carb and when I was reinstalling it had my hand on the dizzy. when I went to get up the dizzy rotated some. I moved back approximately how much it turned but not exact. The clamp was not very tight.
I have not used the boat very much in the last two years because of family obligations, I am trying to get it right in hopes of using it more. I never had to adjust timing in the past it has never been an issue. Thank you for the help!

Ok makes sense. Is the carb correct now ? Assume it was a float/needle & seat issue? if it is still an issue may need to check the fuel pressure

 

[Happygolucky]

You answered my next question, so there are versions without the knock sensor?

 

[Happygolucky]

Yep some engines ( like mine..)obiviously came without the knock sensor/control .

 

[JohnSz]

Yep some engines ( like mine..)obiviously came without the knock sensor/control .

FWIW: I had the same year 350 2brl Mercruiser in a '97 Bayliner capri 2050 and it was T5 and no knock sensor. I always grounded the pur/wht wire. Jumping it to 12V? That might not be good for the module. They are hard to find and expensive. Probably better to convert ignition. It was good you asked prior to doing.

 

[Happygolucky]

FWIW: I had the same year 350 2brl Mercruiser in a '97 Bayliner capri 2050 and it was T5 and no knock sensor. I always grounded the pur/wht wire. Jumping it to 12V? That might not be good for the module. They are hard to find and expensive. Probably better to convert ignition. It was good you asked prior to doing.

The jumping to 12v is what you do when you set initial timing with the "Delco EST Voyager "Distributor installed.

(as opposed to the "Thunderbolt V" which you Ground as previously stated )