Questions on a 1983 mercruiser alpha 1

[wildmaninal]

Not to familiar with I/Os. I got the motor freed up and now I'm trying to get fire through the plug wires. I haven't bought any parts besides a condensor and I got a few coils laying around to fit right on it. My cousin came up and he helped me with the boat for a moment, he's not a boat mechanic but is familiar with automobiles. He noticed that there was a hot wire hooked to the negative side of the coil, after tracing it down we found that it was hooked to a temporary push button, maybe the kill switch or a reset button but I don't think it was original it is located right below the throttle/shift control. I took a test light to the positive side of the coil when I first got the motor freed up, and the light was really dim when touching it to the positive post. After removing this live wire from the negative side of the coil and checking it with a test light again it lights up bright.

We got fire to the points but no further, every time we moved the points with the switch on we moved the points manually with a screw driver and it gets spark. Now when we spin the motor over it doesn't fire at the points which I believe we should be able to see. At first we haven't messed with the gap on the points, then we tried setting them to different gaps still nothing. Distributer cap looks good, points look good, plug wires look good, rotory button looks good new, and the condensor is new. Just because everything looks good doesn't mean anything I know.

What to try next?

Also......I noticed at the circuit breaker there is a black wire with a purple ring around it that has been cut off. This same wire along with it's buddy another black wire with a green ring around it, both wires are toasted and both run to the outdrive and I have no clue on what they are for.

Any ideas on the wires?

Are they trim guage wires?

 

[jerryjerry05]

Re: Questions on a 1983 mercruiser alpha 1

If you have power to the points then no further.Change the points.
That switch is probably an interupter switch.The switch when shifting out of gear stalls the motor for second so the drive can shift.The original switch is on the control panel where the shift cables meet.As far as the other wires who knows????????Jerry

 

[wildmaninal]

Re: Questions on a 1983 mercruiser alpha 1

I did sand these original points down with a fine grit sand papper, may try them again. If I recall right I read on another thread that the gap should be set and where from .22 to .35 or something like that.

Is that correct.

 

[littlebookworm]

Re: Questions on a 1983 mercruiser alpha 1

I strongly suggest that you pick up a manual for the engine to help you sort everything out. Hopefully, get a Mercruiser manual, as it's the best. The two wires that are"toast" are probably, but not certainly, going to the tilt limiter switch in the outdrive. They prevent the drive from being tilted up too much. You should really begin with a tune-up, adjusted properly, with new points set with a feeler guage and a dwell meter. Good luck. Hy

 

[wildmaninal]

Re: Questions on a 1983 mercruiser alpha 1

Better yet I got it running . I put the points back on set the gap and with the aid of some gas on a rag and my cousin we got it to fire up and it sounds pretty good.

I still want to do a compression check on the motor. Can't wait to try it out. I don't know what the normal temperature is on that motor it was reading about 180 on the temp guage. I ran it by sticking the fuel line down in a gallon jug filled with gas. We took the built in tank out and drained it of the old gas in the mean time, which to my surprise I put a little on the ground and lit it up with a lighter, but I still don't trust it. I put water in the tank also, I guess I done right, you could see it starting to cerculate (or at least I believe it is) through the cooling system. I ran it on muffs also. From my eyes the bellows on the outdrive look good.

What should the temp read on that motor?

How do I check the lube in the outdrive?

My father said it was making a noise in the outdrive but I put it in gear and all works well from what I see.

 

[Don S]

Re: Questions on a 1983 mercruiser alpha 1

You have a lot of answers so far, but all without knowing what engine you actually have?

 

[wildmaninal]

Re: Questions on a 1983 mercruiser alpha 1

Motor serial number 6797623, 4 cylinder alpha one 470 3.0 liter mercruiser, 1983 model. On a bomber fish and ski boat. My bad :redface:, I guess I didn't realize that alpha one can have 6 or 8 cylinder on it.

 

[Don S]

Re: Questions on a 1983 mercruiser alpha 1

4 cylinder alpha one 470 3.0 liter mercruiser,

Those are 2 different engines. Which do you have really???? A 3.0L Chevy engine or the 470 Mercruiser ............. Uhhhh engine?
Got any pictures?

 

[achris]

Re: Questions on a 1983 mercruiser alpha 1

That serial number comes up as Don's favourite... 3.7litre 470..

 

[Don S]

Re: Questions on a 1983 mercruiser alpha 1

Yea, I got the same thing when I tried again. Think I included the comma in the Copy and Paste I did on the SN. It said it wouldn't work the first tiime, and assumed it was too old to pick it up.

What a shame, new to IO's and he has a 470.

Anyway
Here's a link to the OEM service manual. You WILL need it.
http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/08/cover.pdf
About 355MB in size, don't get in a hurry.

 

[Bondo]

Re: Questions on a 1983 mercruiser alpha 1

What a shame, new to IO's and he has a 470.

Ayuh,...... What a way to Start,.......

 

[achris]

Re: Questions on a 1983 mercruiser alpha 1

You guys are just too hard... A well maintained 470 is as good as any other I/O. Now, let's start helping the poor guy...

Have you done a compression test yet?

Cheers and good luck,

Chris.............

 

[wildmaninal]

Re: Questions on a 1983 mercruiser alpha 1

You guys are just too hard... A well maintained 470 is as good as any other I/O. Now, let's start helping the poor guy...

Have you done a compression test yet?

Cheers and good luck,

Chris.............

I made a special trip outside in the middle of the night (just about) to make sure that this motor said 470 on the valve cover and it is a 470 Mercruiser .
By the way it sounds I'm going to pretend I have something worth my time lol.

Sorry for the late reply, been gone all weekend fishing with my brother. I haven't done a compression check, if I get time tomorrow I will do a compression check been wanting to do one anyway. The motor will crank right up and run with me holding the choke plate down.

I know if the compression is good I am going to put a manual choke on that motor, the automatic choke is messed up. I don't know if I'll be able to just simply hook any manual choke up to the carb or not like you can on an older automobile engine.

 

[wildmaninal]

Re: Questions on a 1983 mercruiser alpha 1

I did the compression check.

cylinder #1 = 145
#2 = 80
#3 = 130
#4 = 155

Now I don't know if it needs a ring job or valve job or has a blown head gasket or maybe even a cracked head or maybe it just needs a decarb.

 

[Don S]

Re: Questions on a 1983 mercruiser alpha 1

Do a modified leak down test on it. Pressurize the cylinder while it's up on TDC of the compression stroke for #2 cylinder. (Valves will be closed)
Then listen for where the air is escaping.
Hear air out the carb, the intake valve leaks
Oil fill cap on the valve cover, rings or piston.
Exhaust = exhaust valve.

 

[wildmaninal]

Re: Questions on a 1983 mercruiser alpha 1

Do a modified leak down test on it. Pressurize the cylinder while it's up on TDC of the compression stroke for #2 cylinder. (Valves will be closed)
Then listen for where the air is escaping.
Hear air out the carb, the intake valve leaks
Oil fill cap on the valve cover, rings or piston.
Exhaust = exhaust valve.

Alright. I was wanting to try and make a fitting with a valve stem on it to do the leak down test but I have a comrpession test fitting or air tool fitting that I can hook an air tank to it but this will constantly put air to the cylinder. Don't know if that will be alright or not.

 

[Don S]

Re: Questions on a 1983 mercruiser alpha 1

That is what you are going to need, it will leak down fairly quickly. Yes, you can use the compression tester hose, just remove the tire valve stem in the end of the hose, or you won't be able to put air into the cylinder. You will only need 50 or so PSI to do the test to find out what's bad.
Just have the flame arrestor off, and the oil cap off the valve cover. You WILL hear which one is leaking. You can pull the riser off to hear the exhaust if you want, but if it's not going past the piston or the intake valve, it has to be going past the exhust valve.

 

[wildmaninal]

Re: Questions on a 1983 mercruiser alpha 1

Well I done the leak down test 2 times today. The first time I attempted it it did blow back through the carb, but I don't think it was TDC. I did it a second time and didn't here anything.

I am going to take it to the lake tomorrow and run some decarb through it, maybe cruise around (not at full speed if I can help it).

What is the chance that it might have a stuck valve or rings being that the motor was froze up?