3.7 no crank

[Scott Danforth]

its a simple motor with a simple points ignition. with the understanding of mechanical things, it should be easy to figure out.

 

[achris]

It's little more than a car engine. Just make sure you use marine rated parts for anything fuel or electrical.

 

[nola mike]

Didn't the OP say that it cranked when a battery was connected to the slave, or did I misunderstand? If that's the case, why is everyone concerned about a mechanical issue rather than straight electrical?

 

[Dschaffer]

Didn't the OP say that it cranked when a battery was connected to the slave, or did I misunderstand? If that's the case, why is everyone concerned about a mechanical issue rather than straight electrical?

I did say that and have determined that it must be something electrical. Here is where it gets really weird. Per suggestion from this forum, I pulled the drive today. To my surprise, the engine cranked with the plugs in. I had to use both (all) batteries as it did not crank with just the one. I am 99% sure that the new cranking battery I bought is bad. I put the drive back on and strangely enough, it cranked with ease. I hooked up water and tried to get her to fire. After about 10 seconds of cranking and basically “running” via the starter, I stopped turning the key to give the starter a break. After a minute or so I tried to fire it again and no crank no nothing. I wiggled and jiggled wires and even cursed a bit. She cranked, or not, and tried to fire several times, sporadically, with no rhyme or reason over the next half hour. I have zero idea what is going on. It is possible that I could go out right now and she would crank, maybe fire, or do nothing at all. I’m at a loss. Any ideas are very welcome. Thanks

 

[achris]

You have a bad connection somewhere. And that could also mean the connection, on the negative side. Check all your negative cables, and the 'connection' between the starter and the engine block!

Chris.......

 

[Dschaffer]

You have a bad connection somewhere. And that could also mean the connection, on the negative side. Check all your negative cables, and the 'connection' between the starter and the engine block!

Chris.......

Thanks man. I feel like I have looked over and cleaned all major cables but I think you are right. I’m not able to picture/remember the starter to block connection at the moment. I did clean all the wires on the starter but maybe missed the engine ground? I will check it out tomorrow. Thanks again. I wont leave this thread hanging. Wether its me or the boat shop, I will post what the solution is.

 

[Scott Danforth]

by clean, you used 320 grit or a wire brush on the end of a drill, right. the connections need to be shiny, then after you bolt them firmly, you need to seal them with electrical varnish

if the battery cables are stiff or have green fuzz coming out near the terminals, replace the cables.

 

[Dschaffer]

by clean, you used 320 grit or a wire brush on the end of a drill, right. the connections need to be shiny, then after you bolt them firmly, you need to seal them with electrical varnish

if the battery cables are stiff or have green fuzz coming out near the terminals, replace the cables.

Pretty much. I used sand paper and a wire brush. I did not seal them but am planning on it once I figure out what the problem is. I will have some time this afternoon to mess around and am planning on returning the new battery tomorrow.
Thanks again

 

[Dschaffer]

A new clew. It is still cranking a firing intermittently (sometimes I turn the key and nothing, sometimes she cranks and fires). But here is a new observation. Now that I’ve gotten some fuel moving through it she is wanting to run but as soon as I release the key from the “fire” position, it shuts off. It appears the key needs to be fully turned for it to stay running. What’s going on?

 

[Bondo]

as soon as I release the key from the “fire” position,

Ayuh,...... That's the "Start" position of the key switch,.....

Check the key switch with a test light,.....

You need power out the ignition post to the purple wire, with the key in the "On" position,......

If you have power there, check the tiny (+) terminal on the coil, with the key "On",.....

 

[Dschaffer]

Ayuh,...... That's the "Start" position of the key switch,.....

Check the key switch with a test light,.....

You need power out the ignition post to the purple wire, with the key in the "On" position,......

If you have power there, check the tiny (+) terminal on the coil, with the key "On",.....

There is power out of the ignition with the key in “On” position. No power at the + side of the coil but the wire going to the choke from the positive side of the coil was smoking and super hot.

 

[Bondo]

No power at the + side of the coil but the wire going to the choke from the positive side of the coil was smoking and super hot.

That's Impossible,....... reread what you wrote,....

 

[Dschaffer]

That's Impossible,....... reread what you wrote,....

That’s what I thought. I’ve tried it with a test light and volt meter both ground to the battery. There is power at the choke. What is the second wire coming out of the choke? It’s purple.

 

[Dschaffer]

According to this https://forums.iboats.com/filedata/fetch?id=7047772, it looks like the purple wire is the power from the ignition switch. The wire that goes from the choke to the ignition coil is a resistance wire. Mine is gray though, not purple.

 

[Dschaffer]

The gray wire at the choke and at the ignition coil, gets super hot with the key in the on position. I disconnected the wires at the choke and at ignition coil and they still get hot. There is power at the choke wire but not at the ignition wire. How is this happening?

 

[nola mike]

Post a picture of your set up. It doesn't sound right. The purple wire from the ignition should be 12 volts with the ignition on. The resistance wire should also be purple, and supplies eight or nine volts or so to the coil with the key in the on position. That's what keeps your engine running. Check the resistance of your gray wire to see if someone replaced the purple with just a regular non resistance wire. The resistance wire gets pretty hot, but definitely shouldn't smoke. The only gray wire at the coil should be from the tach, to the negative terminal. The purple and yellow wire to the coil is from the slave solenoid, and supplies with full 12 volts while you're cranking the engine only. If the resistance wire isn't supplying voltage to the coil, then the engine will attempt to fire and then die as soon as the key moved back to the on position.

 

[Dschaffer]

The grayish wire looks like it could of been light purple, once upon a time.

 

[Dschaffer]

Post a picture of your set up. It doesn't sound right. The purple wire from the ignition should be 12 volts with the ignition on. The resistance wire should also be purple, and supplies eight or nine volts or so to the coil with the key in the on position. That's what keeps your engine running. Check the resistance of your gray wire to see if someone replaced the purple with just a regular non resistance wire. The resistance wire gets pretty hot, but definitely shouldn't smoke. The only gray wire at the coil should be from the tach, to the negative terminal. The purple and yellow wire to the coil is from the slave solenoid, and supplies with full 12 volts while you're cranking the engine only. If the resistance wire isn't supplying voltage to the coil, then the engine will attempt to fire and then die as soon as the key moved back to the on position.

I get 10 volts at choke with the key on. I will mess around with it more tomorrow. Do you see anything out of the ordinary in the pictures? It ran fine last fall before I winterized it. There were a few occasions over last season when nothing would happen when i turned the key but it never lasted long so I wasn’t really able to troubleshoot it. This is the first that I’ve ever noticed the hot and smoking wires.

 

[nola mike]

Ok, that looks correct. Yeah, that gray wire probably started its life purple. You should have a full 12v at the choke with the ignition on, and it should be slightly less than that at the coil (+) with the ignition on. So you have at least one problem there. Guessing that you're getting 12v to the coil when cranking (from the slave solenoid), but not enough from the ignition wire (choke) to keep it running. For diagnostics, might want to run a known good 12v to the choke and see what happens. You'll have to chase down where you're losing voltage starting from wiring harness-->ignition-->back to the choke after that if it works.

EDIT: What is the voltage at the (+) terminal of the coil in the run position?

 

[Dschaffer]

Ok, that looks correct. Yeah, that gray wire probably started its life purple. You should have a full 12v at the choke with the ignition on, and it should be slightly less than that at the coil (+) with the ignition on. So you have at least one problem there. Guessing that you're getting 12v to the coil when cranking (from the slave solenoid), but not enough from the ignition wire (choke) to keep it running. For diagnostics, might want to run a known good 12v to the choke and see what happens. You'll have to chase down where you're losing voltage starting from wiring harness-->ignition-->back to the choke after that if it works.

EDIT: What is the voltage at the (+) terminal of the coil in the run position?

Thanks for the insight. The + side of the coil is now reading 1.4 in on and 10.6 in run. The choke was reading 10.6 in on but then seemed to drop to 9.5ish once the wires got really hot. I put a new battery (replacing a new battery) and it now cranks with just the single new battery. NAPA told me the new battery that I returned, read good. That obviously wasn’t the case. Just happy they let me swap it out. Now the gear on my starter is busted up. It spins great but doesn’t always catch. I suspect that if I had gotten a good new battery the 1st time around, before messing with everything else, I wouldn’t be having these problems. I’m hoping to have some time tomorrow to get into the wiring. I guess I need to order a new starter as well.
Thanks again.