un-sticking Chevy (OMC) 350 V8

[tschmidty]

The wiring is pretty basic so it won't be too much of a problem, but figure it out afterward and redoing it will be a pain. I'd see if you have a boat salvage near you that you can get the full wiring harness from another OMC.

[gbmacca]

Hi

My Detoit 8v71's went under and 9 months later, after loosing my insurance claim, tried to turn them over after removing all injectors. My research said a mix of Acetate and gearbox oil, by far the best 'deruster' and after letting sit for several days, then with a long bar, try to turn over.
If yours is a caste iron block, rings will have rusted to side of bore, so if slowly turned, you may save, but think if you remove head and look for scratch marks down cylinder - it will tell you.

Good luck!

Gbmacca

[wayne.b]

Originally Posted by gbmacca

My research said a mix of Acetate and gearbox oil, by far the best 'deruster'

===


I believe you meant to say acetone instead of acetate. A 50/50 mix of transmission fluid and acetone is a very good penetrating oil.

[travis_farmer]

so, i got my used distributor installed, and installed some fresh spark-plugs. then i cranked it over, and over, and over... nothing. thinking the distributor was 180 degrees off, i put the #1 back to TDC, with the rotor 180 from where it should be. pulled the distributor, turned the shaft 180, and re-installed. then i cranked, and cranked, and crank... battery died.
so now i have the battery on the charger.
one thing i checked is if the coil was making spark, but got nothing, though it is getting power. so it looks like maybe the coil is bad. just my luck. could be the battery was simply not charged enough to turn the starter, and produce a spark. either way, i will know in a few hours of charging. i don't happen to have a timing light, but even with rough blind timing, it should at least pop and fart now and then.


~Travis

[Bill Seal]

Simple troubleshooting:
Take off the distributor cap, jiggle the points with a screwdriver, see if the coil throws a spark. (hold the high tension wire a short distance from the block, or in your hand if you're brave- or stupid.)
Pull #1 plug, (or all of them if your battery is weak) put your thumb over the hole, crank the engine over, see where the rotor is pointing when it pops your thumb off, THAT'S #1 wire.
Simple.

[travis_farmer]

Originally Posted by Bill Seal

Simple troubleshooting:
Take off the distributor cap, jiggle the points with a screwdriver, see if the coil throws a spark. (hold the high tension wire a short distance from the block, or in your hand if you're brave- or stupid.)
Pull #1 plug, put your thumb over the hole, crank the engine over, see where the rotor is pointing when it pops your thumb off, THAT'S #1 wire.
Simple.

i did check the coil by the points, and holding the coil wire near the block. and i found #1 by using the mark on the balancer, and the timing indicator.


~Travis

[a64pilot]

it will almost certainly run, do you have the valve covers off so you can see if any valves are stuck?
Then there is the farmer method of checking for compression by seeing if it will blow your thumb off of the sparkplug hole

[travis_farmer]

I have a compression tester (surprised i haven't checked it yet...), and i will give that a go next session. right now i am re-charging the battery, as well as my own.


changes thus-far: i have made a simple switch and a button setup. switch supplies power direct to the coil (i found it was a dead circuit, though fine before. will get to that later), and a button supplies power direct to the starter solenoid. i found the coil to be emitting a very nice fat spark with this setup, and i didn't have to keep running to the ignition key every time i made a change.
also, i have disconnected the fuel line from the tank, when i found it was bad gas, and inserted the fuel line (input to pump) into a tank of fresh gas. the carb is giving gas to the engine (maybe flooded, will check for that too, next session).


confirmation on firing order? Chevy 350 Firing Order and HEI Distributor Cap Specs - HCDMAG.com
that's what i used. not sure if a marine engine is different for some reason.

i have confirmed #1 TDC by poking a screwdriver through the plug hole to gently feel for the piston (hand crank only, of course). after confirmation of #1, i tried setting the distributor 180 degrees again. still no cough, pop, or fart. i will also drain the carb float bowl, before i try again, to ensure fresh gas.


not sure if i will try again today, due to the time it takes for a usable battery charge, and tomorrow is predicted rain. in any case, i deeply thank you all for your help thus-far. i only wish somebody would stop in and perform some sort of magic.


~Travis

[jpmesa]

We un-stuck an old WW 2 jeep in Hawaii that was frozen for at least 20 years. Put kerosene into the cylinder and let set for several weeks. Worked it free with a big wrench (by hand only). No rebuilding kits back than at least not in Hawaii. Jeep was still working last time I was there.

[a64pilot]

I think all US V8 engines firing order is 1,8,4,3,6,5,7,2.
Some of course are labeled differently, I’m referencing #1 being front the front left.
Then to throw a wrench into things on Marine twin engine, it’s not uncommon to have one turn backwards thereby giving you counterrotating props.
I doubt yours is a backwards turner though.

[travis_farmer]

I’m referencing #1 being front the front left

left facing the front pulley, or the bow of the boat?
i have it wires (as per diagrams on the web) with the right, when facing the front pulley.


~Travis

[jimbunyard]

I've never seen a stock 350 Chevy intake that didn't have the cylinders numbers and firing order cast into it...

[jimbunyard]

Additionally, coils do go bad, but dirty or incorrectly set points, or a bad condenser, are far more frequent causes of weak spark.

As previously noted, top dead center is not enough; there is a top dead center on the exhaust stroke also.

If you time the engine so that it fires on the exhaust stroke it will never run, though it will spit and sputter.

As suggested, you can just put your finger over the plug hole, or check that both valves are closed when the piston is at the top.

There are a couple of ways to align the distributor.

Usually the cap has a '1' stamped on it. If you're going to use that as your start point to wire the plugs, you'll have to put the engine at TDC on the compression stroke and then insert the distributor so that the rotor aligns with the '1' on the cap. This often takes several tries, and you have to move the oil pump shaft so that it aligns as the distributor shaft rotates as it engages the cam gear. Sounds more involved than it (usually) actually is...

The other way is just to stick the distributor in, again with the engine at TDC on the compression stroke, and then wire the distributor with wherever the rotor winds up pointing as the number one cylinder, and going from there. This is a sure way to confuse (some) future mechanics though, and it may also leave some of the plug wires at odd places or too short...

[travis_farmer]

Hmm, i remember seeing that on a different engine, a while back. i didn't think of it on this engine i guess. that intake in the image is exactly how i have it wired. if that is correct for my engine, it must be the bad fuel causing me trouble. i will simply drain the carb, and see what happens when the fresh fuel gets to the engine.


i mean, if the timing was an issue, i should get at least a pop or fart now and then. the plug wires could be suspect, but again, i should get something. my guess is likely a fuel issue.


~Travis

[jimbunyard]

If you can see fuel coming out of the accelerator jets when you actuate the throttle (providing it's gas that is coming out), fuel isn't the problem.

Just to verify, you did ensure that the engine was at TDC # 1 on the compression stroke when you inserted the distributor, and that the rotor pointed to the same position on the cap that you have the #1 plug wire going to?

Also doesn't hurt to be sure the plugs are wired in the same direction as the distributor turns.

If you're not getting a fat blue spark from the coil where the hi-tension wire plugs into the distributor, you need to find out why before attempting to actually start the engine. If you have a good spark and the engine is correctly timed (very roughly is usually good enough), the engine should start with either starting fluid or a tablespoon or so of gas poured into the carburetor. Put the spark arrestor back on if you use gas though; engines being coaxed back to life have a bad habit of backfiring through the carb, especially when not particularly in time...