Mercruiser timing

[Submariner1]

I am trying to set up the timing on my 1999 3.0L Mercruiser (GM). I have a Clymer manual and it states <br /><br />"Disconnect the shift interrupt switch from the engin harness, then connect the engine harness wires together. Do not allow the shift interrup swich wires to contact each other."<br /><br />Does this mean connect the wires coming from the engine wiring harness together. I have tried this and the engine almost stalls and I then have no indication of timing marks when I use the timing gun.<br /><br />My timing can't be that far out?? What I am I doing wrong.<br /><br />I have also connected the jumper wires to each of the white leads extending from the distributor as indicated in the manual.<br /><br />Help please.

 

[tommays]

Re: Mercruiser timing

this link goes over it you have to connect the shift wires together temporarialy for the motor to run<br /><br />the wires on the distributor put it into a base timeing mode<br /><br />i have a 1995 3.0 with EST i dont no if a 1999 is the same<br /><br />i have the Clymer manual and find it only a littel better than nothing but not much<br /><br /> http://www.marinemechanic.com/site/PAGE257.htm <br /><br />tommays

 

[Laddies]

Re: Mercruiser timing

you must unplug the wires at the shift interupter and plug them together [a pur. and white/grn. wires to diconnect the switch then connect the two white wires that come out of the dist. to gather with a jumper wire your timing should be at 1 degree BTDC the jumper disables the electronic spark advance. [the dist mod. are troublesome]--bob

 

[Submariner1]

Re: Mercruiser timing

Thanks for the replies. <br /><br />What you have told me to do is what I have done. I think.<br /><br />I warmed the engine up to its normal temp. <br /><br />I installed a jumper wire across the 2 white leads coming out distributor (as shown in the link),<br /><br />I unplugged the shift interrupt switch (2 black wires from the grn/white and purple wires) and connected the grn/white and purple wires (from the wiring harness) together. <br /><br />As soon as I do this the engine almost dies, idle lowers and I get no timing marks on the timing gear cover using the timing gun.<br /><br />Still don't know what is wrong.

 

[rodbolt]

Re: Mercruiser timing

try rotating the dist body while using the jumpers. its normal idle timing is about 10*BTDC when put into base timing mode it locks out all electronic advance.set the idle timing to spec,usually 1* BTDC then remove all the leads and insure idle timing moves up. we had some module problems that would not go to full advance and made for poor running engines. with the delco EST it is imperative to retest at wot with the boat in the water or on a dyno. in the service manual it should give you the specs. if not it is in the merc service manual.

 

[Submariner1]

Re: Mercruiser timing

According to the manual the timing for the engine that I have should be at 2* ATDC.

 

[Don S]

Re: Mercruiser timing

According to the manual the timing for the engine that I have should be at 2* ATDC.

I sure wouldn't put a lot of trust in the timing specs of a Clymers manual.<br />What is the Serial Number of your engine.<br />There was 3 different timing specs for the 3.0L and none of it went by engine year.

 

[Laddies]

Re: Mercruiser timing

when you disable the spark advance the timing goes into the retard and causes the engine to lose rpm thats why you set the timing so slow the spec.that I gave you and procedure I gave you came from a mecruiser manaul number 13 --bob

 

[Don S]

Re: Mercruiser timing

Service Manual 26 is for the 98 and newer 3.0L and there are 3 serial number breaks.

 

[Submariner1]

Re: Mercruiser timing

It worked!!! I have the timing set correctly.<br /><br />What originally worried me was that I could no longer see the timing marks once I connected the white wires on the dist using the jumper and plugged the two interrupt switch wires together.<br /><br />Once you all confirmed that what I did was correct and suggested that I rotated the the dist slightly, the timing marks showed up. It was easy from there.<br /><br />2* ATDC was correct for this model (marked on flame arrestor). <br /><br />Thanks all for your input and suggestions.<br /><br />For your info this all started from a leaking heat exchanger that causes the motor to overheat, which caused the head gasket to blow, which lead to me having the head shaved, resetting the valves and finally getting the timing correctly set. I'll be watching that temp gauge a lot more closely in the future. Thanks again.<br /><br />Norm