Timing marks?

[glennj3]

I decided to check my engine MC 165 timing before I consider pulling the carburetor off again. I believe I saw 6 degrees BTDC listed for it. I have the timing light and I can crank her up, so at idle, I need to ID the correct mark to use.
Thanks

 

[glennj3]

I see 3 metal marks on the engine. There should be a mark on the fly wheel. I turned the engine over several times but could not locate anything on it. Any help?

 

[Alumarine]

Is this the 4 cylinder 165 or the 6 cylinder?
It's the harmonic balancer I believe that has the timing notch/mark.

 

[glennj3]

Yes sir, the 165. I called the harmonic balancer the flywheel, sorry. I probably need to turn the engine with a wrench socket to move it slow enough to find it.
The engine has 3 marks on it, my book shows them with 0,5 and 10, then on the harmonic balancer it has F on the left of the line and T and T to the right across from the timing marks. Not sure what they are for.
But 6 deg BTDC would be just above the 5 mark.
I do not see a vacuum line to the distributor, does it just use the centrifugal plates?

 

[Fishermark]

Yes sir, the 165. ...

Both the 4 cylinder and the 6 cylinder are referred to as the "165." It sounds like you have the 4 cylinder? (They're very different engines).

 

[Alumarine]

It does sound like it's the 4 cylinder.
Timing might be 4 degrees BTDC.
Once you hook up the timing light you should see the timing mark easily on the harmonic balancer.

 

[glennj3]

I am using the 1964 to 1985 Shop Manual so it has a lot of different things in it.
All of the 165's call for 6 BTDC.
I turned the HB and found the mark. Now I will mark it with whiteout and check her tomorrow. All set up and ready.
Again assuming the mark I need is at above the 5 degree mark on the engine?

 

[Alumarine]

Is it an actual Mercury manual or some crummy incorrect aftermarket? That's pretty wide coverage for an actual Mercury manual.
Are you sure that spec is for the 4 cylinder engine?
Why not split the difference and make it 5? And yes, use the 5 degree marker on the motor.

 

[glennj3]

It is the four cylinder, the book is by Clymer, intertec, yes probably an aftermarket.
I checked the timing, it was so far up I could hardly see it with the timing light. I moved it down to 6 degrees.
Tach at 600 RPM. I checked the points and had to adjust them to 0.019, they were gapped too far open.
Gave her some throttle while watching the timing. It did not advance right away. I had to get up to around 900 to 1000 for it to advance much. She advance to about 10 degrees. She was also stalling while moving up to 1000 RPM.
I can open and close the points with the rotor, so that works.

 

[glennj3]

I re set the timing to just below the 5 degree. I removed the distributor plate and cleaned and checked the springs and plates. All seemed to work well and was clean.
It does advance noticeably by 900 RPM but simultaneously it is stumbling hesitating until it gets over 1500 RPM then zooms up quickly.
Idle jet screw has to be out 4 to 5 turns to run anything other than idle.
I have removed the carb again but not sure what to do with it since I just overhauled it. Will remove the jets make sure they are all clean.
I need to remove the choke plates so I can put it together easier. How do you get them on again after filing down the screws that hold them on?

 

[Alumarine]

Here's a link to a manual that might help if your's falls into these years.
Sounds like a carb problem now.
Sorry, I have no experience with these motors.
Is compression ok?

http://boatinfo.no/lib/mercruiser/manuals/mercruiser8.html#/0

 

[putback]

5 turns on the screw & bogging under 1500 sounds like partially clogged carb circuits. All the passages before fuel can get to the jets. Lot of narrow restrictions and small 90 degree turns in the casting that collect a lot of gunk over the years. Its usually worthwhile to completely disassemble the carb and blow through all the fuel passages and vents with a common rattle can of carb cleaner, one with the plastic tube that will fit in the holes. Do it over a white rag and you'll be surprised what comes out. Pay special attention to the accelerator pump circuit. Most have two small steel check balls in the circuit. The one under a fine coil spring loves to stick closed. The one under the accelerator pump sits in a spot where any water in the carb collects and corrodes the steel ball. Usually you have to pay top $ to get a kit with the check balls.

 

[stonyloam]

Original timing on a 470 was 8 degrees btdc, but that was changed to 4 degrees btdc after they had some problems with the poorer quality modern gas ( if you can't get it to run smoothly at 4 you might move it bit to 5 or 6 if that helps). Run 89 or 91 non ethanol gas if you can get it. If you still have points in the distributor you need to set the dwell, as well as the timing. BTW a 470 does not have a harmonic balancer it has a ROTOR, yeah I know Picky Picky but you should get the nomenclature correct. Once you get the timing and dwell correct you can address the carb., the idle screw should affect the idle and not higher RPM. Turn the idle screw all the way in and then out 1 1/2 turns. See if you can get it idle at 650-700 RPM, using the idle stop screw. Turn the idle screw in till it sterts to stumble, then out until it starts to stumble again, then turn it in until it is running smoothly. Then leave it there. If you are still having problems with acceleration, it is probably some other part of the catb.

 

[glennj3]

I have another post on, Cant get the engine to run smoothly. I addressed all of these issues. I moved the timing to 6 BTDC, ran new gas through to the carb. No changes. Just removed it again, taking it to the shop for a professional (I hope)!