5.7 omc stalling while shifting

[Nick_1987 5.7 OMC]

Ok do you still have points ignition? If so & the points haven’t been replaced in a while a bad condenser can cause what you’re experiencing. This happened to me once before. I usually Change points when they get pitted or it starts running bad out of the blue.

Point have not been serviced in 2 seasons. They were replaced then.

 

[Nick_1987 5.7 OMC]

Ok do you still have points ignition? If so & the points haven’t been replaced in a while a bad condenser can cause what you’re experiencing. This happened to me once before. I usually Change points when they get pitted or it starts running bad out of the blue.

How can I fix the points or re adjust them?

 

[Lou C]

well now you gotta go learn how breaker points igniton work. you set the gap when the dist. cam is on the high point, but then check with a dwell meter at idle speed. Gap & dwell are inversly related, small gap = large dwell angle. It is actually the degrees that the dist cam turns, when the points are closed. When the points are closed they are engergizing the coil via the primary side of the ignition system, & creating a strong magnetic field in the secondary windings. When they open the magnetic field that was created collaspes and induces a high current in the secondary ignition system. So that's how it works. The condenser absorbs the current flow to prevent the points from burning up too fast.
Auto shop 101 circa 1970s. I learned on a 1965 VW Beetle 1200 cc.

 

[Nick_1987 5.7 OMC]

well now you gotta go learn how breaker points igniton work. you set the gap when the dist. cam is on the high point, but then check with a dwell meter at idle speed. Gap & dwell are inversly related, small gap = large dwell angle. It is actually the degrees that the dist cam turns, when the points are closed. When the points are closed they are engergizing the coil via the primary side of the ignition system, & creating a strong magnetic field in the secondary windings. When they open the magnetic field that was created collaspes and induces a high current in the secondary ignition system. So that's how it works. The condenser absorbs the current flow to prevent the points from burning up too fast.
Auto shop 101 circa 1970s. I learned on a 1965 VW Beetle 1200 cc.

Here’s my little filter, looks pretty gummed up

 

[Lou C]

That’s used in the auto applications if you have the large water separating filter like I do you should have the screen filter there.
We had a 1975 Olds Delta 88 350 with the Quadrajet and that’s the filter we used.

 

[Nick_1987 5.7 OMC]

That’s used in the auto applications if you have the large water separating filter like I do you should have the screen filter there.
We had a 1975 Olds Delta 88 350 with the Quadrajet and that’s the filter we used.

This one?

 

[Lou C]

Yes

 

[Nick_1987 5.7 OMC]

Yes

Here is a video of the motor running at idle, after new fuel line and replacing auto filter with the proper screen filter.

 

[Nick_1987 5.7 OMC]

Here is a video of the motor running at idle, after new fuel line and replacing auto filter with the proper screen filter.

Also adjusted the fuel mixture.

 

[Nick_1987 5.7 OMC]

well now you gotta go learn how breaker points igniton work. you set the gap when the dist. cam is on the high point, but then check with a dwell meter at idle speed. Gap & dwell are inversly related, small gap = large dwell angle. It is actually the degrees that the dist cam turns, when the points are closed. When the points are closed they are engergizing the coil via the primary side of the ignition system, & creating a strong magnetic field in the secondary windings. When they open the magnetic field that was created collaspes and induces a high current in the secondary ignition system. So that's how it works. The condenser absorbs the current flow to prevent the points from burning up too fast.
Auto shop 101 circa 1970s. I learned on a 1965 VW Beetle 1200 cc.

The misfire did not dissapear. I did not touch the points yet… it happens just after 2500rpm. Changed fuel line, fuel filter and screen filter in the carb. I’m not sure how to adjust the points yet. Just a little confusing… any guidance will be much appreciated!

 

[Lou C]

Ok here is a Prestolite points distributor. To adjust you need a set of feeler gauges and a dwell meter. Put it on the dwell meter with the engine running (+ terminal goes to - on coil, - terminal goes to ground) and see if it matches the spec for you engine. If it does, then that's not the problem. If it is off, you have to adjust. In this pic you can see there is a screw near the breaker points then there is an opening in the point plate, were you can put a screwdriver to pry the points themselves to open or close the gap. You do this with the engine set so that the rubbing block of the points is on the high point of the distributor cam. Check with feeler gauge, clean with rubbing alcohol, then re-check with dwell meter. Then set timing and idle speed.

 

[Nick_1987 5.7 OMC]

Ok here is a Prestolite points distributor. To adjust you need a set of feeler gauges and a dwell meter. Put it on the dwell meter with the engine running (+ terminal goes to - on coil, - terminal goes to ground) and see if it matches the spec for you engine. If it does, then that's not the problem. If it is off, you have to adjust. In this pic you can see there is a screw near the breaker points then there is an opening in the point plate, were you can put a screwdriver to pry the points themselves to open or close the gap. You do this with the engine set so that the rubbing block of the points is on the high point of the distributor cam. Check with feeler gauge, clean with rubbing alcohol, then re-check with dwell meter. Then set timing and idle speed.

What do you mean by set timing and idle?

 

[Lou C]

timing is setting when the #1 spark plug fires, in relation to top dead center, it is adjustable by turning the distributor which is normally held still by a clamp, idle is just the idle speed. I think you need to get a factory shop manual it will be very helpful. Start reading on how basic breaker point igntion systems work. Then read up on carburators. If you have a Rochester Quadrajet that is a pretty complex carb, not really for beginners. I've been doing this stuff since I was about 16, that's 50 years lol. To me it is second nature.
Dwell angle, timing, idle speed.
Its easy for people my age because all that old technology in your boat, was new technology in our cars, 50 years ago, lol! We had the same Chevy 350 cu in engines with Rochester carbs, and points distributors as our daily drivers. Either you learned how to fix it, paid to get it fixed, or got stuck somewhere. Knowledge was a good thing to have!

 

[Nick_1987 5.7 OMC]

Turns out my father knows how to mess around with these things. Points looked alittle ****, also what looks like rust around them. We replaced the points and everything and set the gap to what looks like 0.017. No gauge to check. Motor starts easy and runs ok. But I can’t get to wot. Is this a point issue because they are not gapped properly ?

 

[Lou C]

Point gap determines how long the coil is saturated & therby the strength of the spark . Under the point plate is the centrifugal mechanical advance. This uses flyweights to advance the timing as rpm goes up & springs to retard it as rpm goes down. If they are stuck by rust you won’t get full timing advance. In the pic I posted of the Prestolite you can see a wick in the center of the distributor shaft, this is where you’re supposed to put a few drops of oil to lube the weights. To fix your boat you need:
A factory shop manual (eBay)
A multi meter that measures dwell, rpm, voltage & ohms
an advance timing light
Anything else & you are just guessing but won’t be right.

 

[Lou C]

Here's your tune up specs:
idle speed 500-600 rpm in fwd gear
point gap 0.018"
dwell angle 30*+- 2*
timing 8* BTDC
spark plugs Delco MR44T gap 0.035"
I would also check total timing advance with an advance timing light at the specified RPM to make sure that the centrifugal advance is working, this unit should add 21* advance at about 3200 rpm so your total would be 8*+21*=29* total timing advance. You need the advance timing light in my pic above to measure that, with boat in the water so you can run it in neutral at 3200 rpm.
Also, what prop do you have on the boat? The wrong prop won't allow you to reach the specified rpm at wide open throttle, so that is another thing to check. Your spec is that the engine should reach between 4200-4600 rpm at WOT, but I like to see it toward the higher end of 4600. This means less strain every time that little 5.7 has to pull that big Bayliner up on plane. I have mine set for a WOT rpm of 5,000 to lessen the strain on the little 4.3 I have pulling my heavy 20' up on plane (4200 lbs). My boat came with a 14.4x19 prop (wrong, it was ok for a V8) I tried a 15x17 (better but still not there) and wound up with a 15.5x15 (best). This lowers top speed but greatly improves accelerating on plane and lowers strain on the engine for longer engine life.

 

[Nick_1987 5.7 OMC]

Point gap determines how long the coil is saturated & therby the strength of the spark . Under the point plate is the centrifugal mechanical advance. This uses flyweights to advance the timing as rpm goes up & springs to retard it as rpm goes down. If they are stuck by rust you won’t get full timing advance. In the pic I posted of the Prestolite you can see a wick in the center of the distributor shaft, this is where you’re supposed to put a few drops of oil to lube the weights. To fix your boat you need:
A factory shop manual (eBay)
A multi meter that measures dwell, rpm, voltage & ohms
an advance timing light
Anything else & you are just guessing but won’t be right.

Where is point gap done, when the little ridge on the middle piece is in contact with the arm from the point?

 

[Nick_1987 5.7 OMC]

Here's your tune up specs:
idle speed 500-600 rpm in fwd gear
point gap 0.018"
dwell angle 30*+- 2*
timing 8* BTDC
spark plugs Delco MR44T gap 0.035"
I would also check total timing advance with an advance timing light at the specified RPM to make sure that the centrifugal advance is working, this unit should add 21* advance at about 3200 rpm so your total would be 8*+21*=29* total timing advance. You need the advance timing light in my pic above to measure that, with boat in the water so you can run it in neutral at 3200 rpm.
Also, what prop do you have on the boat? The wrong prop won't allow you to reach the specified rpm at wide open throttle, so that is another thing to check. Your spec is that the engine should reach between 4200-4600 rpm at WOT, but I like to see it toward the higher end of 4600. This means less strain every time that little 5.7 has to pull that big Bayliner up on plane. I have mine set for a WOT rpm of 5,000 to lessen the strain on the little 4.3 I have pulling my heavy 20' up on plane (4200 lbs). My boat came with a 14.4x19 prop (wrong, it was ok for a V8) I tried a 15x17 (better but still not there) and wound up with a 15.5x15 (best). This lowers top speed but greatly improves accelerating on plane and lowers strain on the engine for longer engine life.

Right now I have a 15x15. Not sure if it’s the right one. WOT I’m around 3500-4000rmp.

 

[Lou C]

well I don't know if you can go lower in pitch than that so you need to look for other causes for the low rpm....because that's way too low and is causing a lot of engine strain every time you pull the boat up on plane, like trying to start up in a manual trans car in 3rd gear.
as in...
make sure when your throttle control is in WOT position, the throttle blades in the carb are in WOT position (accel cable adjustment)
check for any restrictions in fuel supply...large cannister filter....anti siphon valve on gas tank, fuel tank vent
any other carb issues, are the secondary air doors (also called air valves) opening properly on the Quadrajet, these are spring loaded vacuum operated doors that cover the secondary throttle valves which are mechanically operated, there is a spring adjustment on these...if the open too soon (spring to loose) it causes a bog when accelerating, if too tight may never open
Accel pump, the seals do wear out, so you have to replace it...
tune up and total timing advance as I said above, this is really important
if you go through each possible cause you'll get it. I started with a lousy 4200 rpm max at WOT, now it consistently pulls 5000 easy.

 

[Lou C]

some pix of the Quadrajet air horn & main body....