Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

[ewpvic]

It's not where I think it SHOULD be on this engine and I am trying to check and reset.

Thanks

 

[Live-liner]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Front of motor to the port side. There should be a line on the rotor that is bolted to the crank. Tab is stamped on see picture

 

[Eric 3.7LX Alpha 1]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Also see the attached TSB regarding timing for the 470

 

[ewpvic]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Thanks guys. I thought that MIGHT be it, but better to ask. I read the TSB, Eric. May be why I'm getting some noise under load.

 

[Eric 3.7LX Alpha 1]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

might not be a bad idea to also check the timing advance. If the weights and springs under the mounting plate for the points get corroded, your advance might be out of spec. Do you have the chart that shows what the advance is suppose to be?

 

[ewpvic]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Somewhere, I think. Mounting plate? I changed points plugs wires. She runs pretty well on muffs, but under load is a whole other thing. I'm gonna shoot a video today if it's not timing.

Gave her a real good tune up, since she sat out for a season. I'm a 5.7 guy, but I'm starting to become fond of this little power house.

 

[Eric 3.7LX Alpha 1]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

In the distributor under the cap. The mounting plate that the points and condenser are screwed down to...... Remove that plate and under it are the advance weights and springs.

They are great on fuel and have loads of torque.

 

[wrestling coach]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

might not be a bad idea to also check the timing advance. If the weights and springs under the mounting plate for the points get corroded, your advance might be out of spec. Do you have the chart that shows what the advance is suppose to be?

I agree. Worth the 15 minutes to clean and lubricate.

Dennis

 

[ewpvic]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Ok, evidently I DON'T have that chart...

 

[Eric 3.7LX Alpha 1]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Here's a link to Service Manual 8:
the link should open up to the advance chart in section 4B
Boatinfo - Mercruiser Service Manual nr. 8 - 1985-1989 - Mercury Marine 4 Cylinder Engines

 

[ewpvic]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Ok, couldn't find my old timing light so I went and bought a Craftsman 14065 Advance Timing Light. This one has Pos, Neg and inductive pickup clamp with an advance knob on the light body. Will this one work? The timing mark jumps all over the place when I try and read it.

 

[Eric 3.7LX Alpha 1]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

That light will do nicely... I have it's older brother:


doing a little research....... causes could be worn distributor bushing or distributor gear or the advance weights/springs.

 

[ewpvic]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Once it settled down to idle it didn't jump around so much. Looks like it was still timed at 8 BTDC with the knob set at 25-30.

Corrected to 4 BTDC per TSB. Does this sound right, or am I missing something? Gonna put it in the river in the next hour.

 

[ewpvic]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

A little pinging in higher rpms, but I think I am close. Fresh gas will probably end it too (90+ octane)

 

[Tonyboyscarbz]

Re: Where is timing tab SUPPOSED to be - 1987 Mercruiser 3.7 ????

Somewhere, I think. Mounting plate? I changed points plugs wires. She runs pretty well on muffs, but under load is a whole other thing. I'm gonna shoot a video today if it's not timing.

Gave her a real good tune up, since she sat out for a season. I'm a 5.7 guy, but I'm starting to become fond of this little power house.

Sorry to revive an old thread. Curious what was your solution? It seems I am having the exact same symptoms as you are...