84' mcm228 305 gmc won't start

[firetrk]

Hello all. Just signed up on the forums today. I have been looking at this site for some time. I have an 84' Galaxy with a gmc 305. This thing wants to start but won't. Here's a rundown of what I've done.
NEW carb dynatuned less than 200 miles away.
NEW cap, rotor and pickup
NEW ignition amplifier
NEW fuel pump
NEW plugs
NEW starter
I have spent a fortune on this and haven't even had it in the water yet...

I am getting spark and fuel. I know the gas is good cause I'm pumping it out of a gas can. I KNOW it's in time cause I used the SOLEC book to time it 8* BTDC. This thing is trying to start but it simply won't run. I've checked everything and can't figure out what the heck is going on. This is my first boat and maybe my last if I can't figure this darn thing out. SOMEONE PLEASE HELP!!! I bought the boat from a guy that just died. He took care of it. U can tell. The family said he pulled it out of the lake and winterized it before he got sick. That was AT LEAST 7 years ago. So the thing has sat that long and no one touched it since. I can't think of any other info I can give to help start the think tank suggestions. I'll try anything and EVERYTHING I need to.
Thanks everyone
Adam

 

[gadget73]

Re: 84' mcm228 305 gmc won't start

Is the firing order correct? 1-8-4-3-6-5-7-2 if memory serves. Should also be cast into the intake and on the flame arrestor cover.

Have you checked the compression?

Have you verified the fuel pump is pumping properly? Fuel pressure check or just crank the motor with the pipe to the carb directed into a container to verify action.

Has the large spin-on fuel filter near the pump been replaced? Those are before the fuel pump, so if its clogged it won't pump. If the O ring is completely dry, it may not seal and you might be sucking air instead of fuel. I usually dip my finger in oil and wipe around the rubber seal, but thats just me.

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

Firing order is correct. I have checked it DOZENS of times cause I have taken every plug out on several occasions to blow them off due to being flooded before getting to the point I'm at now. Before, the motor didn't want to do anything. Now it is ALMOST there. It's as close as you can get without it running.

I also have changed the fuel/water filter as you have questioned with a new one. The only thing I have NOT done yet is check compression. I don't see that being a problem since the boat did run fine when it was put up. I know the rings can be damaged due to dry starting but I'm the only one who's cranked the motor since the last guy ran it.

I'm gonna run out and check compression just to give myself some piece of mind knowing that gremlin doesn't come into play.

 

[towman818181]

Re: 84' mcm228 305 gmc won't start

how can you time it to 8btdc with out it running did you stab the dist correctly at tdc and on the no 1 hole

 

[Bondo]

Re: 84' mcm228 305 gmc won't start

I have checked it DOZENS of times cause I have taken every plug out on several occasions to blow them off due to being flooded before getting to the point I'm at now.

Ayuh,... Install a New set of AC Delco MR43T sparkplugs...

Sparkplugs that have been gas flooded are Junk...

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

Timing doesn't require the engine to run..all that's required is a timing light and the engine to crank quickly enough. As far as the plugs, I'll get some new ones today. I don't think that's the problem though. My grandfather says that the plugs would be fine as long as the gas is allowed to disapate. I trust him there because he's worked as a mechanic his whole life. After thinking and testing every known connection, I did find that the green/white wire on the pickup was only running 4.1v. Now, I haven't tested the theory but I think this is only because the voltage increases because it's getting closer firing a cylinder, ie; the metal tab is entering the pickup so the pickup is increasing voltage for when the tab hits center. I did check compression and all 8 cylinders are on the mark. I also back pressured the system and locked the engine on every cylinder, so there's no blowby. The only thing I haven't check yet is polarity on the coil (which I haven't disconnected until yesterday so that is unlikely). I am wondering about the coil as well. I do know the coil is giving good juice. What I don't know is whether it's consistantly giving the juice as I know when a coil begins to go bad, it will slowly lose power. The problem is that there's no way of testing this without buying a new one cause I don't know anyone with a coil that I could swap just to test. Anymore ideas? I'm banging my head against the wall because there's no logical reason why this thing isn't running! It has gas, spark and is in time.

 

[maxxman04]

Re: 84' mcm228 305 gmc won't start

somewhere one of those three things is missing, or not right. gas, spark, compression. otherwise it would run. did you remove distributor at all? have you checked to make sure it hasn't jumped the timing chain? is it gettin the right amount of fuel through carb? is the spark a good blue color, or a weak orangish color?

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

Guys,
The distributer has not been removed. It is timed because we've checked that 4 or 5 times JUST to make sure. Believe me, I thought about that one. I do know that in the run position, both sides of the coil are getting 12v as I tested this yesterday. It has been raining so far today so I will test the jumper idea as soon as I get the new plugs. Do you remember which side is +? Is it purple or gray? Never mind. The SOLEC manual says it's purple.

As far as "trying to run", the motor catching and turning over at a faster rate as if it's ready to run under it's own power and then back to starter power. It does this cycle continuiosly. It's as if it had a little more of something, then it would run. That's what leads me to the coil losing power but at another $50, I would rather know than guess. I do appreciate the coil suggestion and will try as soon as weather permits.

 

[Bondo]

Re: 84' mcm228 305 gmc won't start

an 84' Galaxy with a gmc 305.
After thinking and testing every known connection, I did find that the green/white wire on the pickup was only running 4.1v. Now, I haven't tested the theory but I think this is only because the voltage increases because it's getting closer firing a cylinder, ie; the metal tab is entering the pickup so the pickup is increasing voltage for when the tab hits center.I do know that in the run position, both sides of the coil are getting 12v as I tested this yesterday.

Ayuh,... I've read,+ Reread,... Nowhere do you say just WHAT the Igntion is, or by Whom,....
Carb Either....

Kinda Tough workin' in a Fog.......

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

Bond-o,
I thought about mentioning the ignition type but forgot..:redface:sorry. The carb is a Rochester 4mv and the ignition system is a darned Thunderbolt 4 HEI. I just got a break in rain and tested the coil again. 12v on BOTH sides. WTF? The SOLEC even says the negative side is supposed to be negative. What it doesn't state if it's a ground or not. I don't have the wiring diagram for the instrument panel. I'm gonnna go test something.

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

After checking the system, the coil is SUPPOSED to have a +voltage on the negative side. When the system is ready to fire, the negative side is grounded by the pickup. This leaves no where for the electricity to go except out the top of the coil wire to the distributer. Oh, well. Back to the possibility drawing board!

 

[Bondo]

Re: 84' mcm228 305 gmc won't start

The SOLEC even says the negative side is supposed to be negative.

Ayuh,... Ditch the toliet paper,+ go up to the Adults Only section,+ grab a copy of the Factory manual...

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

Bond-o,
I did hit the sticky before I posted anything and didn't find the link under my year. I think it's been removed.
Details;
1984 GM mcm228r with 305ci 5.0
Thunderbolt 4 ignition
Merc alpha outdrive
ser#6793674
Drive# 6776665
Carb# 17080565

 

[dubs283]

Re: 84' mcm228 305 gmc won't start

check carbuerator fuel filter. it is located at the front of the carb where the fuel line goes into the carbuerator. be VERY CAREFUL when removing fuel line. Quite easy to strip out the hex head on the connection. 1" wrench on the carb and 5/8 flare (line) wrench on the other

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

Dubs,
The fuel filter is okay. In fact, it's bran new as it came with my new dynotested carb.

 

[MikDee]

Re: 84' mcm228 305 gmc won't start

If your plugs are getting soaked, it sure sounds like your carb float is stuck open? How is your oil, does it small like gasoline? That's where excess gas will go. Aside from that, it sounds like it could be very retarded on the timing, does the TDC mark on the crankshaft match when Cyl #1, and Cyl #6 are at top dead center at the same time, or did the counterweight & timing mark slip (like sometimes happens?) Only one of these Cyls. will fire with each revolution of the crank, (a 4 cycle engine) requires 2 revs of the crank to make a complete cycle. That's why your timing could be 180* out

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

MikeDee,
I agree with your line of thinking on the carb issure. However, I neglected to give the detail that it's not every plug. Just a few of them are getting soaked after pumping the carb and turning it over and pumping and turning, ect. That leads me to believe that it won't run because of a lack of spark. The problem is I can't find the resistance #'s anywhere to test the coil. My ONLY option at this point is to replace it.

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

I did finally find the resistance #'s online late last night and tested it first thing this morning to find out the coil was going bad. I have since replaced that and am getting the same results...not running. I'm going back to the drawing board and starting with timing. Post results later.

BTW...I do have the spark tester and have used it regularly when dealing with ignition issues. It's a nice tool to have

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

Okay guys....still need help on this one. Here's the outcome of the timing test. Before moving anything, cyclinder #1 is running 8 degrees BTDC like the book says. Cylinder #6 is running 4 degrees ATDC. So I start from scratch and static time #1 at TDC. Adjust cap, recheck TDC and then put on the timing light.... I get only 1 flash from light. WTH? Check all wire connections (pickup, coil, ignition amplifier and timing light) and try again. Gives me only 1 flash again. Okay! Run to neighbors and ask to verify light is working on his older truck. Light is working like a charm. Back to boat. Connect again and get only 1 flash again. WTH is going on? Take distributor apart to check everything and decide to move it back where it was (8 degrees BTDC). Flashing like it should at 6 BTDC and cylinder #6 is as well.

I think the pickup is shorting out somehow. That's the only thing I can think of because the cylinder should fire at the same point EVERY time no matter how far I move the distributor. The only difference will be how far out of time it gets with every turn but regardless, it should fire. Am I right? The pickup is just a week old but that doesn't eliminate the possibility of the part being defective. What are your thoughts on this? If the pickup is bad, it would explain why the engine won't run...

 

[firetrk]

Re: 84' mcm228 305 gmc won't start

Anyone????