2.4 Bridgeport timing procedure

[Rhinoortiz]

Hey all, trying to find the right information on this. I tried searching but all I can find is how to time a carb motor or laser style EFI. I have the horn style intake on this Bridgeport as well as a brucato acu. Can't seem to find a procedure that directly relates to my setup. Every thing I find says disconnect the white/black wire going to switch boxes but I can't even find them. Also disconnect advance module on port side of head but I don't have one. All I see is a black box with vacuum hose going to it and some wires on the starboard side and a small box in top center with 2 wires. Also because this engine has an alternator kit the flywheel cover with pointer was removed. I'm am going to come up with a make shift pointer today so I can get this dialed in. I want to make sure I'm doing this right so I don't risk damaging the motor.
For reference this is on a 21 foot open bow advantage. Pretty heavy boat ran always in CA/AZ. It has a 2 hole cle running a 4 blade through hub prop. Not a high performance race setup at all. This is a friend's boat that had a massive vacuum leak and I helped him replace some gaskets and now the idle adjustment is way off so we are trying to get it dialed in. I will post some more pics when I get to the boat in a bit.

[Rhinoortiz]

Some more pics of the electronics on here. What exactly do I disconnect to check base and full advance timing?

[25two.stroke]

Don't worry about the white/black wire or advance module, you don't have it. Just follow the carb 200 timing procedure and you will be just right. You can also remove that throttle position module that is on the port side of the block because you are running the brucato. Just un plug the 3 wire plug that goes into the EFI harness and cap it, then take the other 2 wires off of the voltage regulator and put the nuts back on to retain the remaining two wires that go to the rectifier. Roll #1 or #2 (whichever cylinder you are going to time) to TDC with a dial indicator in the spark plug hole, align your pointer with the 0 (TDC) mark or make your own mark, then roll the flywheel back 0.150" on the dial indicator and that is your 25 btdc mark. Then base timing doesn't really matter...put it wherever the motor is happy and you like the rpm: somewhere between 8 atdc and 4 btdc depending on how healthy the motor and reeds are.

[Rhinoortiz]

I noticed there is a vacuum line going to that throttle position module on the port side that Ts into the fuel pressure regulator line. Obviously cap the T line that goes to the module, but that will not affect anything not having it connected anymore? I do not have a dial indicator to go into the spark plug hole. Is there another way of getting the timing marks lined up? Also the procedure you are referring to is the one where you unplug all plug wires except number on and hold the timing arm full advance and read timing at cranking speed correct? Thanks for the help.

[25two.stroke]

I noticed there is a vacuum line going to that throttle position module on the port side that Ts into the fuel pressure regulator line. Obviously cap the T line that goes to the module, but that will not affect anything not having it connected anymore? I do not have a dial indicator to go into the spark plug hole. Is there another way of getting the timing marks lined up? Also the procedure you are referring to is the one where you unplug all plug wires except number on and hold the timing arm full advance and read timing at cranking speed correct? Thanks for the help.

Yep, once you have the timing marks and pointer situated you crank at WOT with all plugs out but #1 or #2 (whichever cylinder you are setting the timing off of) plug grounded to the block so it sparks and activates the timing light. Do not add fuel to the equation. Replace the line from the manifold to the fuel pressure regulator with a continuous piece of hose. Get a dial indicator, don't do it without it...it won't be accurate and the price you could pay is your whole motor...

[Rhinoortiz]

Yep, once you have the timing marks and pointer situated you crank at WOT with all plugs out but #1 or #2 (whichever cylinder you are setting the timing off of) plug grounded to the block so it sparks and activates the timing light. Do not add fuel to the equation. Replace the line from the manifold to the fuel pressure regulator with a continuous piece of hose. Get a dial indicator, don't do it without it...it won't be accurate and the price you could pay is your whole motor...

So unplugging the throttle position module from the harness 3 prong plug (blue,orange,tan wires) so I just leave the plug open or do I need to jump or ground or do anything with those connections?

[pcrussell50]

Then base timing doesn't really matter...put it wherever the motor is happy and you like the rpm: somewhere between 8 atdc and 4 btdc depending on how healthy the motor and reeds are.

Sorry for the hijack...

This is what I've always done... Put the idle timing where the motor is happy.

...BUT... NOW with the bolded bit, you have piqued my curiosity. From 8 atdc to 4 btdc, which end of the scale indicates healthier motor and reed sealing? Is the less advanced, the better the ring and reed sealing?

-Peter

[Rhinoortiz]

Sorry for the hijack...

This is what I've always done... Put the idle timing where the motor is happy.

...BUT... NOW with the bolded bit, you have piqued my curiosity. From 8 atdc to 4 btdc, which end of the scale indicates healthier motor and reed sealing? Is the less advanced, the better the ring and reed sealing?

-Peter

Also interested about this. I ended up around 0° at idle. This motor has newer boysen reeds and pretty good compression.

[OnPad]

You can use the depth needle on a set of calipers to measure .150 (25°), or .462 after the calipers are zeroed at tdc. The rub is,... it doesn't find center dwell of tdc accurately. If that is needed a piston stop can be used. Roll into the stop from one direction, mark flywheel, then roll into the stop from the other direction, mark flywheel, and true tdc is center of the two marks.

[25two.stroke]

Just put a cap over the tps plug so it doesn't drink water. Around 0/TDC is not bad. I find they always end up with the centerline of the trigger puck about aligned with the split between the front and back halves of the block. This is hard to explain, but almost every BP/Oval port/260 end up idling there if they are healthy. The plastic trigger boss where the link rod jumps over to the timing arm...its round. and that ends up over the seam where the block halves come together. This is about 0-2 atdc if I remember correctly.

When I said about the health of the motor...that is assuming that everything else is dialed. Fuel injection correct, fuel pressure right, compression right, fuel octane adequate for the compression...If the reeds aren't seating correctly, too much standoff, cages warped etc. the first thing that takes a hit is the idle speed. It will take more timing to keep it running. Same goes for compression: if you got low compression, poorly seating rings, damaged cylinders below TDC...idle rpm takes a hit cause the crankcase compression is compromised and the motor cant transfer fuel into the cylinders correctly and itll take more timing to keep the motor running. This goes for all 2 stroke engines.

[Rhinoortiz]

You can use the depth needle on a set of calipers to measure .150 (25°), or .462 after the calipers are zeroed at tdc. The rub is,... it doesn't find center dwell of tdc accurately. If that is needed a piston stop can be used. Roll into the stop from one direction, mark flywheel, then roll into the stop from the other direction, mark flywheel, and true tdc is center of the two marks.

I used the piston stop method before on OMCs. That's how most manuals tell you to align pointer and flywheel before the sync process. Didn't think about a caliper. Not a bad way to get pretty close I'm sure.

[Rhinoortiz]

Just put a cap over the tps plug so it doesn't drink water. Around 0/TDC is not bad. I find they always end up with the centerline of the trigger puck about aligned with the split between the front and back halves of the block. This is hard to explain, but almost every BP/Oval port/260 end up idling there if they are healthy. The plastic trigger boss where the link rod jumps over to the timing arm...its round. and that ends up over the seam where the block halves come together. This is about 0-2 atdc if I remember correctly.

When I said about the health of the motor...that is assuming that everything else is dialed. Fuel injection correct, fuel pressure right, compression right, fuel octane adequate for the compression...If the reeds aren't seating correctly, too much standoff, cages warped etc. the first thing that takes a hit is the idle speed. It will take more timing to keep it running. Same goes for compression: if you got low compression, poorly seating rings, damaged cylinders below TDC...idle rpm takes a hit cause the crankcase compression is compromised and the motor cant transfer fuel into the cylinders correctly and itll take more timing to keep the motor running. This goes for all 2 stroke engines.

Got it. 0 seemed to be best idle and speed. I appreciate all the help 25two.stroke

[25two.stroke]

When I had a bridgeport and brucato on my boat it idled like a dream 750 out of gear, 680-700 in gear and wouldn't miss a beat. I could idle through the longest 5 mph zone without my foot on the petal and then smash right up to 100 with no loading up or bog. When you get em right they idle almost like a 4s. I have yet to get a 260 to idle that good.