165 hp mercruiser timing issues

[gunguy]

I have a 1977 Mark Twain with a 165 Mercruiser. I am getting it ready for the season and can't seem to get the timing mark in the tab. I know it probably needs a distributor rebuild. What is the timing supposed to be and is the electronic conversion the way to go with these. If not can I take the points and guts and swap with automotive parts. Also what cylinder do you check base timing with. I have an advance timing light so I will be able to check alot of stuff

 

[Don S]

Re: 165 hp mercruiser timing issues

Get it running BEFORE you change over to electronic. Otherwise you could be fighting 2 problems at the same time trying to get it running.
Your timing should be 6? BTDC at 700 rpm. If your idle is too slow, raise it up a little to get the timing.
Also be sure your point dwell is correct (31? to 34?), before setting your timing.

 

[gunguy]

Re: 165 hp mercruiser timing issues

It is running currently. If the first cylinder to the bow is number 1 then it is not right. I have to advance the light to about 55 degrees to get it to 0. The points are fairly thin and need to be replaced. It has been 20 years since ihave done anything with dwell is there a place to get some info if I do not convert to electronic. Also idle is rough.

 

[Don S]

Re: 165 hp mercruiser timing issues

Dwell isn't going to change it that much. Maybe a few degrees at most. If you are off that far, your plug wires are crossed, or you don't have them indexed properly to the engine.
Forget about where the book says #1 should be on the distributor, get number 1 piston up on TDC of the compressions stroke. Then see where the rotor is pointing. That will be #1. then install the rest of the wires in the proper order.
An OEM service manual is a must if you want to work on your engine and drive systems.

 

[gunguy]

Re: 165 hp mercruiser timing issues

I don't know that I can find a manual till Monday. Is there some way of finding out what the firing order is it is the old Chevy inline six. Also is the first on number 1. I had heard that marine engines fire opposite a car is this true. Brian Thanks for your help so far

 

[Haut Medoc]

Re: 165 hp mercruiser timing issues

1-5 Too young....
3-6 Too old ........
2-4 Just right......

 

[ziggy]

Re: 165 hp mercruiser timing issues

snicker, snicker

1-5 Too young....
3-6 Too old ........
2-4 Just right......

ya learn something new everyday i guess....

I know it probably needs a distributor rebuild.

why do you think that? do you have dwell variation that shows up on yer dwell meter? if it's in question, take it to a distributor shop and have them check it out.

The points are fairly thin and need to be replaced.

replace them then. their pocket change. get them at yer merc dealer.... while yer there get the rest of the tune up parts. fuel filer, plugs, cap, rotor, condenser, points, maybe even plug wires if their 20 years old.... don't use auto parts on yer boat.

get a oem service manual. probably #2... post up serial numbers to get confirmation on that though......

 

[ParallaxBill]

Re: 165 hp mercruiser timing issues

Some folks will or have disagreed with me on this but when I had the same problem with my 250 L6 just after I bought it the only way I fixed it was to make sure the distributor was properly indexed to the motor. This puts the distributor in correct position on installation.
You can sometimes get them to run if you do not do this but your timing light and timing index tab will not line up properly or in the case of mine, not at all.

BTW, I use a pertronix conversion and think this is the only way to go. You can keep your points for a back up but I doubt you will need them. There's nothing like having an engine fire up quick and idles smoothly even when cold.

 

[ziggy]

Re: 165 hp mercruiser timing issues

either this,

Forget about where the book says #1 should be on the distributor, get number 1 piston up on TDC of the compressions stroke. Then see where the rotor is pointing. That will be #1. then install the rest of the wires in the proper order.

or this,

the only way I fixed it was to make sure the distributor was properly indexed to the motor. This puts the distributor in correct position on installation.

will work. my feeling is that it's easier to understand when indexed proper. it just allows ya to follow the book is all.

There's nothing like having an engine fire up quick and idles smoothly even when cold.

yep, but ya don't need electronic ign to have that occur. just a well tuned engine that has everything set to spec. i still run points. after my tune up on fri., sat. at the lake, it fired up faster (well, at least, as fast) than my buddys brand spankin new 220hp fuelie..... what more could ya ask for.....

 

[gunguy]

Re: 165 hp mercruiser timing issues

I will look into these things today and get back on here with any info that I find. Thanks again for the help. My kids really want to get on the lake and it is now in the 70's around here and everyone is getting ready.

 

[ParallaxBill]

Re: 165 hp mercruiser timing issues

"after my tune up on fri., sat. at the lake, it fired up faster (well, at least, as fast) than my buddys brand spankin new 220hp fuelie..... what more could ya ask for..."

Very true! Didn't mean to imply you couldn't do it without electronics. A well tuned 250 or for that matter a Chevy small block with points are a joy to own and work on.

I was just looking in one of my early Motor Manuals and it shows the proper position of the #1 position on the cap in relation to the engine. #1 should be straight up or at the top of the distributor but the best way to get it there is to find TDC (valves closed) on #1, the timing mark will be on the tab, adjust the oil pump shaft (which drives the distributor by looking down the distributor hole) with a long screw driver so that when you install the distributor the rotor will index to the top in physical relation to the engine. If it doesn't line up turn the oil pump shaft until it does. I need to take a picture of it probably. There is a long, drawn out way of doing right the first time but you can get it right by learning the proper relationship of the oil pump shaft/distributor/original correct distributor installation through a little trial and error.
Hope this helps.

 

[Silvertip]

Re: 165 hp mercruiser timing issues

Go to your local library and check out a Chiltons automotive manual from anywhere in the late 1970's backward to 1963 in the full size car or to 1961 in the Nova. The Chevy inline six is the same engine you have in your boat, its just not marinized but mechanically very similar. A matchbook cover will get dwell (point gap adjustment) close enough for the engine to run.

 

[gunguy]

Re: 165 hp mercruiser timing issues

I will look at these things yet tonite and let you all know. Brian

 

[JustJason]

Re: 165 hp mercruiser timing issues

What the heck does that mean Haut? that one went right over my head.

 

[Haut Medoc]

Re: 165 hp mercruiser timing issues

What the heck does that mean Haut? that one went right over my head.

15
36
24
Wimmin's ages.......

 

[gunguy]

Re: 165 hp mercruiser timing issues

I looked at the distributor tonite. The weights are not locked up in the bottom for the advance. When up on #1 cyl. the timing tab is at zero and the rotor is by number one plug wire. Upon further inspection the cap seems to have some electical corrosion inside. The end of the rotor has some as well. Plug wires look ok. Plugs were replaced last summer. The points are definately worn. Very thin looking and some mild corrosion here as well. I think I will replace these and get back on here after they have been replaced. I am wondering if the cap is carbon tracked. I haven't seen this in a long time but I will look closer tomorrow. Thanks to all for your help. I hope to not have a beached clam by the end of the weekend. Brian

 

[JustJason]

Re: 165 hp mercruiser timing issues

Ahhhh... now i get it
I'm 30.... and mine just turned 23