Mercruiser 170 points burning up!!

[aaron1324]

Hey I have heard alot of disscussion about the 170 points, coil, and other things. My problem is my points keep burning up for some reason. This is geting old! I have heard about a resistor wire that might be the problem....or could it be my coil? or the voltage regulator? I checked the resistance of the purple wire and it shows 1 ohm. Can I just buy the coil with the resistor....bypass the purple wire...use my own #14 to replace it and tie it in over at the black box? Please somene help.

 

[DJ]

Re: Mercruiser 170 points burning up!!

How many volts to the coil? If it's over 9.5, that's too much.

Yes, you can buy a resistor coil.

 

[Bt Doctur]

Re: Mercruiser 170 points burning up!!

Still should put a voltmeter on the + side of the coil . a runaway charging system will burn up a coil too

 

[aaron1324]

Re: Mercruiser 170 points burning up!!

I did a volt check on the + side of the coil to ground and it was 9v. I think it might be the wire, I don't know what the specs are on it and what it should read. I think I will get a new coil with the resistor.

 

[aaron1324]

Re: Mercruiser 170 points burning up!!

If the voltage is above 9 volts what would be the problem? I want to eleminate all possibilities!

 

[Don S]

Re: Mercruiser 170 points burning up!!

I did a volt check on the + side of the coil to ground and it was 9v. I think it might be the wire, I don't know what the specs are on it and what it should read. I think I will get a new coil with the resistor.

Did you check the voltage to the coil with the engine running at cruiseing rpm? Like BT mentioned the charging system on those engines can easily put out over 16 volts this also boils batteries and damages electronics.

Just throwing a different coil on it is not fixing anything, just covering it up till something else fails.

 

[ziggy]

Re: Mercruiser 170 points burning up!!

i may be out of line here, but have ya R&Red the condenser?

it's purpose is to prevent arcing at the points.

 

[aaron1324]

Re: Mercruiser 170 points burning up!!

No I didn't check it when it was running, didnt get a chance, I will as soon as I get new points and condenser. Do I have to get these at a marine supply or can I go to my local parts store? If so what do I tell them I need. A.C Delco 4cyl? This problem didnt start till I fired it up this year, it ran great last year!

 

[aaron1324]

Re: Mercruiser 170 points burning up!!

R&Red the condenser? please explain what that is.

 

[ziggy]

Re: Mercruiser 170 points burning up!!

a condenser stores elect. it's in between the coil and the points. when the points separate they create a spark. the condenser absorbs this spark (which melts points and transfers metal from one point to the other) the condenser then dissipates the stored elec. to grd. thus not harming the points.

i've not read this, but would bet it talks about the condenser at some point (no pun intened, ). http://forums.iboats.com/showthread.php?t=329742

if i've described the condenser function in accurately, i'm sure i'll be corrected.

 

[aaron1324]

Re: Mercruiser 170 points burning up!!

I understand the whole theory of it and the magnectic field, Im an electrician. just not an auto machanic. lol Ok this is my bad....I dont think its the points melting down....they don't look melted when I replaced them, so I may be blowing the condencer. All I know is after starting it 5 or 6 times it wont fire again. It ran fine last year. I did a good tune up after I bought the boat. New points, condencer, coil, dist. cap, plugs, plug wires, and a carb kit. It ran GREAT! at the end of the year I noticed my shift cable boot was cracked. So before taking it out this year I had it replaced. I couldnt do it cause it meant taking the lower unit off. I didn't know how to do it. Well the shop that did this for me told me he had to put new points and condenser on it cause after a few starts they went bad. Mind you they were fine last year before parking it. So I thought O.K. not a big deal....well after I got it home I did some work on the motor cover.....complete rebuilt and recovered it cause the old one was rotten. I decided to make sure everything was ok before taking it out. started it a few times and then no fire. I thought what the heck???? I got to looking and the coil that is on it looks 10 yrs old. it's scratched and rusty looking. I thought...I put a new one on last year....it shouldn't look like that....so I still had the old points and condencer that I took off last year when I did the tune up. I put them on and after starting it a few times....well now no fire again.

 

[ziggy]

Re: Mercruiser 170 points burning up!!

http://forums.iboats.com/showthread.php?t=342393

look at #17 and #18 (first link i gave ya was 16). it's the adults only sticky at the top of the i/o forum. lots of good reading there + service manuals. which is a must have tool if ya think your gonna work on your engine/drive...

 

[Banditz]

Re: Mercruiser 170 points burning up!!

Either convert to the non point system as per the adult sticky thing.

Or get you a coil with a internal resistor. then run a 12 volt power wire to it. Best thing to do is tie into a remote on wire so that its only on when you turn on the ign. Then you shouldnt have that problem anymore.

As for the voltage...adult sticky says 4-9 volts. And to have continuity between the tower and each post. THIS IS WRONG! you must have it between the two post...not the tower. I dunno why it says that, hell maybe me and the three people I had helping me do mine all read it wrong! But from what we can tell, it is posted wrong. I did not have it between the post and tower and mine runs great right now! Anyway good luck.