470 Engine turns over but wont start? 1977 Mercruiser

[aarons 470]

Hi all. I bought a clean 1977 boat 2 years ago. Its 470 Ran like a champ but had to jump it at starter. Ignition switch wouldn't work. Recently replaced switch, verified wiring. cleaned almost all connections in dash and engine. Replaced starter solenoid.

I installed an alternator conversion kit. Removed all stator wires and old voltage regulator wires. Cleaned all accessory terminals and replaced switches, all work good.

Installed a volt meter and removed Amp meter. Taped one wire, and swapped the other to opposite terminal. I followed instructions from experienced members on these 2 changes. Voltmeter registers normal when ignition is on.

I couldn't find a wire that went to my old switch to the "B" terminal. Apparently it is just straight power from battery with a 20 amp inline fuse. I added this.

I triple checked and D-electric greased all cap and rotor connections, they look clean. Plug wire connections look good. Scuffed up points and greased. I have voltage at points when ignition switch is turned to right click. Maybe points can go bad even if contact looks good?

I wasn't able to check the spark arc from coil when pulling it out slightly. I'll have to use my kid tomm to turn key while I look. I wired up my stock 65 impala coil to see if that helped, it didn't.

I'm not sure what else to try other than spark jumping off coil to wire. I made sure outdrive was lowered all the way, I have heard there is a safety switch there. My switch at throttle handle is working. In gear it wont turn over, in neutral it does.

I am going to order new points, cap and rotor etc. That will help eliminate problems?

Any ideas would be appreciated.

 

[stonyloam]

OK, try this: take off the distributor cap, and place a piece of insulating material between the points. Pull the center wire from the cap and place it near ( about 1/4 inch) bare engine metal. Turn the key to run, and with a short piece of insulated wire, briefly jumper across the points. You should get a nice hot spark from the coil wire every time you REMOVE the wire. If you do your ignition and coil are OK. Now remove the insulating material and crank it over. Should get the same hot spark every time the points open. Make sure you are getting battery voltage to the coil + when the engine is cranking. If you are getting no spark and have voltage to the coil your points are the problem.

PS The outdrive safety is the trim limit, WAY off the subject, and NOT the problem.

 

[rallyart]

Get an electronic replacement for the points. It's an easy change and much nicer than points.
Are you getting fuel?

 

[Bt Doctur]

electronics are made for people who don't know how to fix anything or who don't want to learn how to fix things.

 

[Eric 3.7LX Alpha 1]

Points are a very easy system to maintain. I still run them. Never had a problem with them.

 

[aarons 470]

Looks like I have some more troubleshooting to try. I am pretty sure I'm getting fuel. Could smell it, and I tried starting it I added some into carb to and nothing,so pretty sure its electrical. Thanks for the step by step Stony curious to see what happens.
Thanks guys, this forum is great.

 

[nola mike]

Don't have a wiring diagram on me, and the '77 is different from my '86 (you don't have a slave IIRC), but the slave solenoid supplies power to the coil when cranking. Someone can chime in on the details since this is in the back foggy recesses of my brain, but that would account for your symptoms.

 

[salty3rd]

An obvious, but sometimes overlooked thing, make sure the rotor is turning when the engine is turning, I have seen a bad distributor cause this sort of issue. If that is good I would put a jumper wire from the positive side of battery to the positive side of the coil to verify you are getting 12V to the coil during cranking. Also have you done a compression check?

 

[Bt Doctur]

Do the test by stony and report the results

 

[salty3rd]

Do the test by stony and report the results

Geez you would think 12+ years of keeping two of these engines up and running would be worth something. Im not discrediting Stony's test, i guess i just assumed arrons already did it.

 

[aarons 470]

Hi guys, Well tonight I decided to throw in some points really quick before I started trouble shooting. Isn't going so well.

These new points are mercruiser, They don't have a stud or a place to attach the small wire connectors. The old ones did. This has a plastic stop that is fitted into the square cut out on the points but it just presses in. Not possible to attach wires?

The stop is a plastic peg so the only option would be to place wire ends in there and the tension from the band would hold it. Wouldn't be a very good connection though.

Trying to attach a single picture, keeps saying the file is to large to use. Tried going into media tab and then adding pictures, same result? If I try to share says file exceeds 2mb for 1 picture.

 

[aarons 470]

Ok I got the new points on. Its strange, the 2 wires dont screw onto these points, they are held by the metal bands tension. did the trouble shooting, my coil was bad. Bought a new one. It is starting up pretty good but its running rough. From seeing cars with bad points in the past it fits description? Maybe Carb?

However I still need to put new plugs in, but these look good. Fuel is older but I had stabil in it. it smells ok and looks ok.


Carb choke wire hookup is totally corroded and I cant remove choke coil to fix, it seems to be part of the carb? Or pressed on very well. I'll save this for another post.


I think it's my dwell. I adjusted inbetween 15-18 with my feeler gauge. (I used the inches not metric correct?),
but not sure I adjusted from the right starting point. I bumped ignition until I was on the highest point on the dist shaft. (Its barely higher) then I adjusted points.

There is a small cutout that lines up with a small cutout in the end of points base. Should I just line this up to get proper dwell?

I also had quite a bit of dark smoke at startup. Is this normal from sitting? I don't remember seeing smoke last time it ran.

 

[NHGuy]

Not a points smart guy, but as I recall the gap is measured with the gauge (feeler) and the dwell with the meter. Someone correct me.

 

[aarons 470]

Update- I did use a feeler to set the points. I thought dwell was a digital method to measure points, but I'm probably wrong.

So I set points to line up with the notch on the distributor plate and right side of points, it ran worse. So I returned points gap to where I have it set at 16th gap labeled on feelers.

Since I got it running half way normal figured time to change oil, It was pretty ugly.

I bought plugs, this def helped some. It fires right up. engine is a little rough but I've read these engines idle rough?

Next I plan to suck old fuel out of tank. And buy a new fuel filter. Current one looks decent though.


I replaced oil pressure sending unit, and temp sender.
New gauges- volt, oil, temp. Engine has really good oil pressure. Haven't run it for more than a minute to check temp, I need to install new impeller first. It barely works.


I would appreciate any suggestions on what else I should check around the engine. I'm getting close to a water run.

I Spent a lot of time in my driveway the last couple weeks, but makes it even better when you turn the key and it starts!

 

[Eric 3.7LX Alpha 1]

Dwell is the amount of time in degrees that the points are closed.

Changing the gap causes a change in dwell. More gap = less dwell and vice versa. Changing dwell also changes ignition timing, but changing the timing does not change dwell.

Dwell should be between 28?-34?. You have to adjust the timing after you set the dwell/ point gap.

Dwell will tell you if the contact lobes on the distributor are worn or uneven, which will effect how it runs.

check this read out from the "Adults Only Sticky" at the beginning of this forum

How To: Tune-up Your Engine with Points Ignition
http://forums.iboats.com/forum/engi...-up-your-engine-with-points-ignition?t=335302

 

[stonyloam]

OK, at this point I would concentrate on ignition problems, and fool with the carb once you get the timing and dwell correct. That said you NEED two tools: a timing light and a DWELL METER/ tachometer. You need the light to set the timing, and the meter will allow you to properly set the dwell and the tachometer will allow you to accurately set your idle RPM.

 

[aarons 470]

Ok will do. I have a nice timing light. I bought It for my old impala awhile back. I don't have a dwell meter though. I will pick one up. Even with the choke wire non existing she starts right up. It probably won't open though as it warms. I can def tell the timing or dwell is off some,


The dwell and timing settings are probably on the sticky?

 

[Bt Doctur]

I would set the point gap at .018 or the thickness of a paper matchbook.Any thing you use to check anything wont work unless you have the gap set first.
Dwell is the amount of degrees the point remain closed usually 28-32 degrees that comes very close to .018 points gap.For every .001 you are closer,the timing increases 1 degree .For every .001 you are loose, the timing retards 1 degree.

So I set points to line up with the notch on the distributor plate and right side of points,

That tells me you don't know how to set or adjust a points ignition . There are plenty of good videos on how to install and set them up. Suggest you google search and watch them to understand the system better. If not your just spinning your wheels

 

[aarons 470]

18 is the max according to merc.
I set them with a feeler gage at 17, split the diff. Mercruiser dealer said 16-18 if I remember right.

I just tried using the notch line up it was worse than my initial set at 17 so I set it back to 17 with feeler.

I set it when my points were on the highest spot on my distributer shaft

ill try 18 and see of it's a little better. Currently It's firing right up, but is a tad rough,

 

[Eric 3.7LX Alpha 1]

Ok will do. I have a nice timing light. I bought It for my old impala awhile back. I don't have a dwell meter though. I will pick one up. Even with the choke wire non existing she starts right up. It probably won't open though as it warms. I can def tell the timing or dwell is off some,


The dwell and timing settings are probably on the sticky?

They're in the thumbnail I have attached in post# 15 click on the thumbnail picture a couple times and it enlarge full page.