383 Initial Startup Problem

[StevNimrod]

I'm trying to get a 383 running on the ground before installing it in the boat. It sounded simple enough but I can't get the thing to start.

If it matters, it's a Merc setup similar to the 5.7 Gen +, but stroked.

I had a machine shop put it together and they adjusted the valves. Also, I'm running an Edelbrock 1410 carb with the out-of-the box needles/seats.

What I've currently done is set the timing (all different ways imaginable: finger over the hole, pulling #1 spark plug and spinning cap until there's a spark, etc.), then hooked up the ignition coil (two grey wires to (-), three purple wires to (+) and a jumper wire from coil (+) to battery (+)). Carb idle mix is set to 1.25 turns out. Ground stud on engine block to battery (-), starter (+) terminal to battery (+) and a remote start switch hooked up between the starter (+) and start terminal.

If I give the throttle lever a few pumps I see a consistent stream of fuel.

When I go to turn it over, the motor turns over but just won't fire. It almost acts like a motor does when you try to start it without the kill switch properly hooked up.

Any suggestions on what to try to get this thing to fire?

 

[jtybt]

Re: 383 Initial Startup Problem

Spinning the dist cap til you get a spark.


You'll get a spark everytime the lobe opens the points...not just #1 cylinder.

Generally speaking, use the 5 o'clock position of the rotor as #1 cylinder. If your #1 cylinder is at TDC and the rotor is pointing somewhere else, you have the dist in the wrong place. Back the dist out and line up the rotor to about 3:30 O'clock, line the oil pump slot with the dist gear and slide the dist down so the rotor comes to rest at 5 o'clock.

 

[StevNimrod]

Re: 383 Initial Startup Problem

Spinning the dist cap til you get a spark.


You'll get a spark everytime the lobe opens the points...not just #1 cylinder.

Generally speaking, use the 5 o'clock position of the rotor as #1 cylinder. If your #1 cylinder is at TDC and the rotor is pointing somewhere else, you have the dist in the wrong place. Back the dist out and line up the rotor to about 3:30 O'clock, line the oil pump slot with the dist gear and slide the dist down so the rotor comes to rest at 5 o'clock.

Thanks for the reply, jt.

It's a Thunderbolt IV ignition system so to my knowledge I don't have points. Maybe I'm wrong, but on the TB-IV I thought if you found #1 TDC and set the static timing using the marks on the balancer, then turned the distributor slowly CCW you'd see a spark if you had the #1 wire out and hooked up to a plug grounded on the block. Am I wrong on this?

That said, I have it currently so the rotor is about pointed to 0500. Are you thinking I'm out of time a tooth or something?

 

[jtybt]

Re: 383 Initial Startup Problem

As long as you're sure you're on TDC of the compression stroke and not TDC of the exhaust stroke, you should start. Check and re-check the firing order. You should get something. If the valves weren't set right, nothing will happen either.

The TB IV will give you full spark as long as the Batt is up, no matter how slow you turn the dist.

Good luck...spark and fuel (and valves) and you should go.

 

[bigbrownbuku]

Re: 383 Initial Startup Problem

the dizzy can be anywhere as long as you know which 1 is number 1. 1.25 turns sounds way too small but that will only affect running as the accel valve will get you started with enough gas. if you have spark check your firing order and lead positioning again. then try turning the dizzy as you crank you will hear the edges of where the timing is way wrong just try and center it as best you can. if that doesnt work start with a compression test.

 

[jtybt]

Re: 383 Initial Startup Problem

Just to go over this again...what 3 purple wires to coil+. There's only one to the ECM...and one gray to the ECM. You have to have the white/green and white/red wires to the correct terminals to the dist(pick-up module), too.

 

[StevNimrod]

Re: 383 Initial Startup Problem

As long as you're sure you're on TDC of the compression stroke and not TDC of the exhaust stroke, you should start. Check and re-check the firing order. You should get something. If the valves weren't set right, nothing will happen either.

The TB IV will give you full spark as long as the Batt is up, no matter how slow you turn the dist.

Good luck...spark and fuel (and valves) and you should go.

I'm almost positive I set it when on TDC compression. At one point I pulled the valve cover to watch the valve action. That said, I'm wondering if it's not a valve adjustment issue. Although, I would then have to question why I paid the machine shop to adjust them!

How big of a PITA is it to adjust the valves? I just don't want to mess with them if something else is the culprit and actually make matters worse.

 

[StevNimrod]

Re: 383 Initial Startup Problem

the dizzy can be anywhere as long as you know which 1 is number 1. 1.25 turns sounds way too small but that will only affect running as the accel valve will get you started with enough gas. if you have spark check your firing order and lead positioning again. then try turning the dizzy as you crank you will hear the edges of where the timing is way wrong just try and center it as best you can. if that doesnt work start with a compression test.

I tried turning it while cranking and still didn't get it to really sound any different that it was.

How much compression should I expect on a fresh rebuild?

 

[StevNimrod]

Re: 383 Initial Startup Problem

Just to go over this again...what 3 purple wires to coil+. There's only one to the ECM...and one gray to the ECM. You have to have the white/green and white/red wires to the correct terminals to the dist(pick-up module), too.

What happened was the marina pulled the old engine and I picked it up (BTW, the SN is OF276159). When the stroker was finished all I did was swap everything over from the old motor.

There were initially two grey and two purple wires hooked up to the coil (it's an aftermarket coil (Accel 140008). When I swapped the parts over I kept it that way, but I had to add another purple wire since I converted from mechanical to electric fuel pump.

As far as white/green and white/red wires go, I'm not at the motor now, but I'm pretty sure I haven't seen them. There is a plug on the back of the distributor that's connected to the main wiring harness somehow. On second thought, I think I know which wires you're talking about. Where exactly are they supposed to go?

 

[krisnowicki]

Re: 383 Initial Startup Problem

are you sure you have spark. BEfore moving anything check the spark and make sure it is blue and hot. I had a TBIV module go bad and I went in cricles only to find out my spark was in and out. DON S has a spark system trouble shooting guide.

 

[StevNimrod]

Re: 383 Initial Startup Problem

are you sure you have spark. BEfore moving anything check the spark and make sure it is blue and hot. I had a TBIV module go bad and I went in cricles only to find out my spark was in and out. DON S has a spark system trouble shooting guide.

I'm sure I have spark. I removed the #1 wire and put a plug in it and grounded to the block. Hooked up power and turned the distributor and saw blue spark. As far as hot goes, I was wondering how bold the spark should be.

I'll have to do some searching and hunt down DON S' guide.

 

[ringmaster72]

Re: 383 Initial Startup Problem

Are you sure you have the plug wires installed on the dist. cap correctly? In the proper order and in the correct locations? Most engine manuals have a picture of how the wires should be arranged. If the order and placement is correct, then you just need to make sure that the dist is in the proper position.

You need to stick something in the #1 cylinder hole (front cylinder in driver's side of motor. turn the motor over until you feel the piston at the top of the cylinder AND both rocker arms should be loose/both valves on #1 cylinder closed. When you feel the piston on #1 and both #1 valves are closed, you are at TDC.

Now, with the motor at TDC AND the plug wires in the proper order, you need to make sure that the rotor is pointing towards the #1 plug wire. This is usually at around 5 o clock like was mentioned earlier, 5 oclock if you are looking at the dist. from the front of the motor.

 

[n2ostroker]

Re: 383 Initial Startup Problem

It's got to be a timing issue.
Turn the motor to tdc and set the dizzy pointing to the #1 cyl. Position on the cap doesn't matter just make sure you start at one and follow the proper firing order. Most caps have the numbers listed on them though. If it doesn't start you're probably 180* off. \Lift up the dizzy turn the rotor and 180 and try again.

Here is the TB IV wiring

 

[n2ostroker]

Re: 383 Initial Startup Problem

Also ~1.5 turns on that carb sounds about right.

 

[StevNimrod]

Re: 383 Initial Startup Problem

Are you sure you have the plug wires installed on the dist. cap correctly? In the proper order and in the correct locations?

You need to stick something in the #1 cylinder hole (front cylinder in driver's side of motor. turn the motor over until you feel the piston at the top of the cylinder AND both rocker arms should be loose/both valves on #1 cylinder closed. When you feel the piston on #1 and both #1 valves are closed, you are at TDC.

Now, with the motor at TDC AND the plug wires in the proper order, you need to make sure that the rotor is pointing towards the #1 plug wire. This is usually at around 5 o clock like was mentioned earlier, 5 oclock if you are looking at the dist. from the front of the motor.

RM,

I've found TDC and set up the timing this way too. I have probably checked 10 times to make sure the wires are in the correct order. That said, my rotor points at the 0500 position when I'm standing behind the motor facing forward. Which would normally mean I'd be 180* out except that my cap is setup such that the #1 wire is in the same position.

 

[StevNimrod]

Re: 383 Initial Startup Problem

Also ~1.5 turns on that carb sounds about right.

I've tried it 1.5 and +/- .5 and it seemed to come closest to starting at 1.25. I think 1.5 is the correct spec though.

Initially my buddy and I thought timing was the issue so we tried a bunch of different stuff - spinning the dist while cranking, triple checking not being 180* off. I'm really at a loss but am convinced it's something simple (which is why I can't do it ).

 

[n2ostroker]

Re: 383 Initial Startup Problem

It's always something simple. best thing to do is back up for a few. Then start over. Check tdc one more time, make sure there is spark, make sure it is on the compression stroke, make sure firing order is correct, etc. Just do a check list.

Also make sure you have fresh gas. If timing is right and you get a squirt or 2 from the accel pump it should fire right up after a few times turning over. It'll start its just something simple your missing.

 

[StevNimrod]

Re: 383 Initial Startup Problem

It's always something simple. best thing to do is back up for a few. Then start over. Check tdc one more time, make sure there is spark, make sure it is on the compression stroke, make sure firing order is correct, etc. Just do a check list.

Also make sure you have fresh gas. If timing is right and you get a squirt or 2 from the accel pump it should fire right up after a few times turning over. It'll start its just something simple your missing.

I'll have a few days laid up with pneumonia so that'll give me time to step away from it. When I get back on my feet I'll check TDC one more time, double check spark, make sure firing order is right, etc.

If all else fails I guess I'll have to get into valve adjustment, but I'm hoping I didn't pay the machine shop to do it wrong. What do you guys recommend on boats, 1/4 turn past zero lash?

 

[wca_tim]

Re: 383 Initial Startup Problem

my experience with the edelbrock 1410 on a 350 or 383 is that they're way too lean - especially in the idle circuit.

couple of things to check regarding the carb once you're sure the spark is right. when you look down the carb while cranking the engine over, if you can see gas running past the needles (down into the intake) the fuel pressure is probably too high.

they can be very sensitive to float height and pretty much never come right from the factory. I have my floats set an 3/8 and 15/16. a little lower than spec, but seems much less susceptable to having the needles overpowered. did that based on someone elses recommendation.

chances are your 383 likes fuel a lot more than a stock 350 - mine sure does. (what the factory jets and metering rods in that carb are spec'd for). your jets will need to be richened up I'm dialed in about right with 6537 metering rods, 116 primary jets and 110 secondaries. That's probably a bit fat on your engine, but those jets and 7147 metering rods would be a great place to start imho. if you don;t have one, the appropriate tunig kit with an assortment in it is nice to have.

finally, you're probably pulling a good bit more vacuum than a stock engine at idle and will have a major hassle with getting things to run right until you swap the step down springs to the silver ones (may be able to back off to blue, but you have to play with it).

minor addition, accellerator pump linkage to the hole closest to the carb body.

1/4 turn past zero lash is just fine for start up. If you;re running a flat tappet cam, break the cam in and then set them hot. depending on what lifters and cam you're running, probably a half turn past zero lash for hot.

does your second pueple wire you talked about go to an oil pressure switch on the side of the engine? It's to cut the engine out when no oil pressure. I might bypass the switch for getting it running on the stand to eliminate another variable.

come to think of it, I had major hassles with electric fuel pumps making too much pressure for both a 600 and a 750 edelbrock until I put a good regulator in it. my 383, with the same carb on it as yours right now, is doing fine on a mechanical. I have a small cheap fuel pressure gauge in the line right next to the carb so i can see what it's doing if there's any doubt.

Good luck with it! and feel free to ask whatever might be helpfull. sounds like what you;re doing is very similar to what I've got in the little boat here now.

 

[jtybt]

Re: 383 Initial Startup Problem

A comp test should tell you if the valves are adjusted wrong.