Just bought a 1977 Grady White Need engine help

[comicazy]

Re: Just bought a 1977 Grady White Need engine help

Here are some pics I took of the distributor. Everything looks to be fairly clean. I know that doesn't mean much as far as the condenser is concerned, but what do you think of everything else? I also took a pic of the gauge. I believe that is not an ammeter correct?

 

[Bondo]

Re: Just bought a 1977 Grady White Need engine help

Here are some pics I took of the distributor. Everything looks to be fairly clean. I know that doesn't mean much as far as the condenser is concerned, but what do you think of everything else? I also took a pic of the gauge. I believe that is not an ammeter correct?
View attachment 192170View attachment 192171View attachment 192172View attachment 192173

Ayuh,.... The Points look burnt in the 2nd picture,....

Yes, that's a Voltmeter.... not an ammeter....

 

[oldsub86]

Re: Just bought a 1977 Grady White Need engine help

done

 

[Bondo]

Re: Just bought a 1977 Grady White Need engine help

I have asked this question before but do not think I have ever got an answer to the question.
If you look at the 2 photos of the distributor, you will see black plastic cup washers on the screws that hold the plate to the body of the distributor. What purpose do they serve?

Ayuh,... They index the cap.....

 

[Hoosmatroos]

Re: Just bought a 1977 Grady White Need engine help

You definitely need new points.

 

[comicazy]

Re: Just bought a 1977 Grady White Need engine help

Alright, just purchased the kit that Don posted. I'll get that installed once it gets here and report my results.

 

[oldsub86]

Re: Just bought a 1977 Grady White Need engine help

done

 

[comicazy]

Re: Just bought a 1977 Grady White Need engine help

Well it's time to report my findings. I've put new points, condenser, rotor, and spark plugs in. I did manage to get it to run for maybe a full second two or three times. After that, nothing. It seems that I am either getting a lot of resistance, or too high of compression or something. It will not turn over with just a battery connected. I had to have my truck hooked to it and running to get it to turn over, and even then it has a hard time getting a full revolution. The only other possibility I can think of is maybe high resistance in the battery cables. ie: corrosion. Unless anyone has any other ideas, my next step is going to be replacing those.

 

[Don S]

Re: Just bought a 1977 Grady White Need engine help

Bad starter, rust in the cylinders, garbage battery cables, poor connections.

Just a few of the possibilities of why the engine will not turn over easily.

 

[comicazy]

Re: Just bought a 1977 Grady White Need engine help

Hmm, alright. Well I guess I'll start with the easy fixes for now then. New battery cables and clean connections definitely won't hurt it. Hopefully tomorrow is as nice as today was. Hate when it has to rain on my day off.

 

[comicazy]

Re: Just bought a 1977 Grady White Need engine help

Well, cables replaced, turn over a bit easier now. Even got it fired a few times again. Just doesn't seem to want to keep running. To me it seems like a carb problem. It squirts gas if you push the throttle forward, but I'm pretty sure that's just the power valve. Any ideas on what to look at next?

 

[stonyloam]

Re: Just bought a 1977 Grady White Need engine help

I think it is time to do a compression test. Won't be very accurate cold, but will give you some idea if the condition of the engine.

 

[comicazy]

Re: Just bought a 1977 Grady White Need engine help

Compression test done.
Results:
Cyl 1-140psi
Cyl 2-140psi
Cyl 3-135psi
Cyl 4- 60psi

Diagnosis?

 

[Don S]

Re: Just bought a 1977 Grady White Need engine help

You could play around and do all sorts of leak down tests, etc. but on a 470 engine. Pull the head and look. The problem will be obvious.

When you pull the head, just make sure to keep all the lifters and valve parts in order so they can be put back in the same place.

 

[comicazy]

Re: Just bought a 1977 Grady White Need engine help

Ok. You almost sound as though you know what I'm going to find. Are we talking hole in the piston type obvious, or where's Waldo obvious? Lol.

I've also posted a video of me trying to start the engine. Just in case it may help in any way.
Trying to start my boat - YouTube

 

[matt167]

Re: Just bought a 1977 Grady White Need engine help

3.7's are what is known as an open deck design. What you most likely have is a head gasket blown and compression is blowing into the colling passage which surrounds the cylinder ( hence the open deck design ). Very common to find in this engine type, especially if they get hot.

Almost forgot, I think you have too much initial ignition timing so it's laboring the starter. Loosen your distributor clamp and turn the distributor back a little, have someone hit the key. You might get it running that way, but it's going to start harder with 3 cylinders.. Possibly have a bad starter or bad connections tho, so check them.

 

[stonyloam]

Re: Just bought a 1977 Grady White Need engine help

We are talking blown head gasket, maybe bad valve on #4. I had almost exactly the same symptoms. Follow the procedures in manual #8 EXACTLY Boatinfo - Mercruiser Service Manual nr. 8 - 1985-1989 - Mercury Marine 4 Cylinder Engines if you don't have it. Make sure you do not mix up the pushrods. Use a OEM Mercruiser head gasket, it is specially designed for the 470, the aftermarket HG's are auto gaskets. You might consider hardened exhaust seats while you have the head off. Good luck, lots of help here.

 

[nola mike]

Re: Just bought a 1977 Grady White Need engine help

May be obvious when you pull the valve cover (and he means OBVIOUS). If the exhaust manifold riser/gaskets are leaking, it tends to go to the #4 cylinder. FWIW, I used an auto HG when I replaced mine. Probably have a couple of hundred hours on it since then without issue...
And based on the condition of the wires to the regulator, I'd be suspect of all your main connections...

 

[comicazy]

Re: Just bought a 1977 Grady White Need engine help

Ok, so before I go tearing the motor apart, how would I go about getting this running. I'm sure that without the proper compression, that #4 cylinder isn't going to fire. So should I just pull that plug for now so that cylinder isn't even in the equation? On the distributor adjustment, should I be turning it clockwise or counter to help it start easier? Just trying to make sure this engine will in fact run. It will even on only 3 cylinders right? Just wont be very powerful. Thanks for all the help guys.

 

[nola mike]

Re: Just bought a 1977 Grady White Need engine help

Not sure why you would want to try to get it running without figuring out what was wrong. You could have something going on that running will worsen...
"Tearing the motor apart" will take you maybe an hour to remove valve cover (maybe see problem there) and/or head (certainly see problem there).