mercruiser wont start

[rcwjona1]

I had allot of help from family and friends, all gone home now. My husband is doing the best he can but not a motor guy. I bought century 1981 it had a mer cruiser 305, it was seized. I had it replaced with a small block (truck motor) 305. I took all the marine stock off the old engine and put on new engine. The engine fired once. Now all it does is click. My friend tried to get it started and the wires from the distributor to the engine started to smolder. I when to marina for wiring harness they said there isn't one, I will have to replace each wire one at a time. Is there an diagram that will show what gage wire, and where each wire goes? any help would be great

 

[Fishermark]

Re: mercruiser wont start

Welcome aboard!

If you go to the top of the page, there is an "adults only" post - (It is named that just to grab your attention. ) Once there, you can download a manual for your engine that contains a wiring diagram.

Having said that, which wires are smoking? Smoking is from excessive heat - which can mean a few things... such as... short circuit... bad / loose / corroded connection... battery installed backwards... those are just a few possibilities.

 

[Fishermark]

Re: mercruiser wont start

Also - if your engine harness is shot, there is a good chance you can find a used one cheap on ebay.

 

[jtybt]

Re: mercruiser wont start

Hopefully you didn't use the old starter. That could be your problem. Especially if the wires that are smoldering are going to it. It could mean the solenoid contacts are frozen on the 'ON' position and the starter isn't turning because of a bad connection(not enuff juice getting to it) or it's just plain frozen/rusted up.

Need to know what wires are burning up.

The 305 was a poor choice for a replacement compared to a 350 from power to price. If it was a used motor out of a truck, there are other issues.

These are things you should have asked PRIOR to the engine swap.

 

[Don S]

Re: mercruiser wont start

What color was the wire that was smoldering?

 

[legoman67]

Re: mercruiser wont start

if its clicking and not turning over, odds are you have a bad main connection to the battery, or a bad starter solinoid.

start at the battery, take each large lead off 1 at a time and clean them up with like 150 grit sandpaper until they are mostly shiny, do the same to each end of all the large main leads, and the surfaces they attach to aswell... if that does not solve the clicking problem, then you probably need a new starter solinoid

once its cranking over, then u can troubleshoot ifit wont start.

Carburated v8 engines are very simple to wire, and you can easily wire them from scratch with basic wiring and engine knowledge... i rewired an old engine in about an hour and it works fine..

 

[rcwjona1]

Re: mercruiser wont start

new batterys, new starter, new leads to battery. wires that are smoldering are next to alternator like 10wires wound in electrical tape.

 

[totx]

Re: mercruiser wont start

What color was the wire that was smoldering?

If you want help, answer the questions...

 

[rcwjona1]

Re: mercruiser wont start

the wire the were smoldering and taped together are red.

 

[rcwjona1]

Re: mercruiser wont start

is a mer cruiser positive ground or negative ground? its a 1981 century cuddy cabin.

 

[Don S]

Re: mercruiser wont start

Has it ever worked since the new engine was installed? It may be that some wires were hooked up wrong. The red wires are not fused, and if hooked directly to ground will melt and burn.
What model was this engine before you changed it?

 

[Don S]

Re: mercruiser wont start

NO, it's not a positive ground.

 

[rcwjona1]

Re: mercruiser wont start

the new motor turned over once, than when tried again it just clicked. The old motor was a mer cruiser 305. Thats why we got the 305 small block so it would be compatible. After my friend put gas in carburetor, hooked up battery, than was about to turn key switch it started smoldering. He never tried to start it because of the wires were smoldering. I have a mer cruiser manual but it doesn't show diagrams real well, or we can't read it right.

 

[totx]

Re: mercruiser wont start

the new motor turned over once, than when tried again it just clicked.

After my friend put gas in carburetor, hooked up battery, than was about to turn key switch it started smoldering. He never tried to start it because of the wires were smoldering.

I have a mer cruiser manual but it doesn't show diagrams real well, or we can't read it right.

Was the battery removed after the first time it turned over?
And the second time it just clicked.

Was the battery hooked up with right polarity at the 3th attempt?
When it start smolder...

What type of manual do you have?

 

[rcwjona1]

Re: mercruiser wont start

I was told that the battery was hooked up right every time. I have a seloc mer cruiser stern drives 1964-91. I have a feeling we are not smart enough to fix. Unfortunately we are not engine savvy. If anyone mechanical is in my area i would be very grateful. I have a feeling that a wire is grounding everything out.

 

[totx]

Re: mercruiser wont start

The engine fired once. Now all it does is click.

So this is wrong?

It just smolder

 

[Fishermark]

Re: mercruiser wont start

The system is a negative ground. The big cable from the negative post on the battery needs to go to the engine block. The big red cable needs to go from the positive of the battery to the big terminal on the starter. I would check those connections before doing anything else.

And yes, it might be time to take it somewhere.

 

[totx]

Re: mercruiser wont start

I have a seloc mer cruiser stern drives 1964-91.

Read post # 2 AGAIN

(Get a Mercruiser service manual for that engine)

 

[legoman67]

Re: mercruiser wont start

remove the tape around the melted wires and figure out were they go to, try to figure out which one cauaed the problem, and seperate from the ones that just received damage from the heat. tell us what it connects to and from.

sounds like maybe someone tried to connect positive to a sensor on the block by the description of wire location, or possibly the alternator is bad...

 

[wca_tim]

Re: mercruiser wont start

If your wiring harness is fried, I second the above note that you can find a decent one on ebay often times. I would NOT use different color wire to replace the old, because it will just add confusion for anyone trying to work on it in the future.

if it were me, i would:

carefully unwrap the section of wiring harness where it was smoking, and see that you didn't melt anything together. that'll have to be addresed first. Noe that if it looks like they just got hot and you got it disconnected fast enough to keep major damage from happening, i would move on to the next step and come back to upgrade the wiring once you know where the problem.

using the wiring diagram in the manuals from the adults only section, check each and every connection carefully before you put power to the battery again. make sure they're all correct. hopefully you'll find something that is crossed from pos to negative. note that if you were shorting from positive to negative somewhere, it would only click because you'd be pulling batter charge down fast... worry about making sure all of the connections are right and chances are that if you get the wiring right, the starter will work out fine.

Hope this is helpful. I know that it's frustrating when you jump off the diving board on something like this. hang in there and you'll get it.