1976 Mercruiser 233 Ford 351w no start

[pmklesne]

Brought home my first 233 hp 351w 1976 Sea Ray. Started up with muffs before I purchased. Got home and experienced troubles getting it started again. Was able to start it twice in driveway only to take to lake no start- and has never started again. Serial number of motor is Merc 4677439. I can tell PO has messed with wiring, but ignition wiring harness appears to be correct. Cranks and cranks, no start. I purchased volt meter and have begun troubleshooting. Purchased clymer manual, so I have wire diagram and have looked at it a million times. I bought and installed new quicksilver solenoid, ignition coil and coil lead to distrib cap. I am getting 12 v to solend starter and alternator. With key on, I'm getting 12 v to choke and + side of coil. Resistance wire ohms out fine. I thought maybe bad interrupter switch, but disengaged brown wire to bypass for test, but still no start. I believe I have everything wired correctly..... Oh and I do get a good spray of gas into the carb.... I am getting 12 v from ignition coil lead that goes to distrib cap. I'm at my whits end... Im thinking it could be points??? Any advice will be greatly greatly appreciated.

 

[Bondo]

Im thinking it could be points???

Ayuh,.... Welcome Aboard,..... That's the most logical place to look,....

The points are what fires the coil,....

 

[pmklesne]

What is best and quickest way to test points?

 

[Bondo]

Ayuh,.... I take it ya haven't even popped the distributor cap off,..??

Count on the points bein' burnt, 'n in need of replacement,...

The points are an annual throw-away replacement part,....

1 side of the points should have voltage from the coil's (-) terminal, the other side is grounded,...

 

[pmklesne]

Ok thanks, I'll try and report back

 

[Brandon5778]

Ok thanks, I'll try and report back

You may try taking a file and filing the points a little and see if that gets you started. They get dirty/corroded easily. If that works still replace them along with condenser rotor and your cap.

 

[haulnazz15]

Another item to check is your base timing/plug wire orientation after you've pulled the distributor cap off and verified the points are good. Base timing on the 233 (351w) should be 10BTDC, plug wires oriented 1-3-7-2-6-5-4-8 going counter-clockwise around the distributor cap.

 

[kenny nunez]

There were 4 different distributors that could be on your engine. Mallory, Prestolite, Holley & Ford. You will probably have th match up the points and condenser at a NAPA store or just get it over with and install a Petronics kit.

 

[pmklesne]

All good info, thanks. I'll try cleaning/setting points and see if that works for short term troubleshooting. Any advice or lessons learned if I install petronix?

 

[Bondo]

Any advice or lessons learned if I install petronix?

Ayuh,..... Ya don't have to replace the points every year,.....

 

[pmklesne]

Ok... update. I replaced points and condenser. Gapped points to spec. Still no start. I've still got 12v to selonoid. With key on... I've got 10.7v to choke and only 4.6v to +side of coil. I'm really confused now. I disconnected coil lead from distributor and cranked the key..... Shouldn't I see a spark? I see no spark, in the dark?

 

[pmklesne]

So, just a follow up... I also relplaced distributor cap, rotor and plug wires, and new spark plugs. Still not starting, but I then had good spark! Replaced carburator and tried it...... STARTED! However it runs real rough ... not like before- when it purred. Timing? Or dwell? Or both? The idle screws seem to have little effect on how rough it's running???

 

[Bondo]

Timing? Or dwell? Or both? The idle screws seem to have little effect on how rough it's running???

Ayuh,.... Timin', 'n dwell are apart of changin' the points, so,... Ya,....

'n carbs rarely run Perfectly when slapped on, outa the box,.... They also need Fine Tunin' to run right,....
What carb are We talkin' 'bout anyways,..??