New Engine, Turns Slowly NO START

[brapperdoodle]

Finally got some kinks sorted out on my brothers 550SX I have been building. Unfortunately today I finally got to the point of starting and the engine turns very slowly with a fresh battery. Acts like the battery is almost dead, but it is new. Tried multiple batteries, same result. Wont turn fast enough to start, not even close. The engine turns smoothly by hand and so does the drivetrain with the engine out. If I remove the spark plugs, the engine spins over like normal. But if you put the plugs back in, it seems like it has too much compression and the starter can't spin the engine hardly at all. Im really stumped, does anyone have some suggestions?

 

[Ancelmo]

Finally got some kinks sorted out on my brothers 550SX I have been building. Unfortunately today I finally got to the point of starting and the engine turns very slowly with a fresh battery. Acts like the battery is almost dead, but it is new. Tried multiple batteries, same result. Wont turn fast enough to start, not even close. The engine turns smoothly by hand and so does the drivetrain with the engine out. If I remove the spark plugs, the engine spins over like normal. But if you put the plugs back in, it seems like it has too much compression and the starter can't spin the engine hardly at all. Im really stumped, does anyone have some suggestions?

Make sure the motor is aligned properly mine was doing what sounds like the exact same thing until i broke the midshaft. Do the battery or starter cables get hot?

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[brapperdoodle]

Make sure the motor is aligned properly mine was doing what sounds like the exact same thing until i broke the midshaft. Do the battery or starter cables get hot?

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Motor is aligned perfectly, but that is a good thought. Yes the ground wire smoked and I replaced it with an 8g wire that runs directly to the starter body. Not the battery ground cable, the other small ground wire.

 

[Ancelmo]

Motor is aligned perfectly, but that is a good thought. Yes the ground wire smoked and I replaced it with an 8g wire that runs directly to the starter body. Not the battery ground cable, the other small ground wire.

Did you figure out what originally smoked the ground? Have you put a meter on the starter to see if you lost any voltage at starter. Sorry just kind of spitballin ideas

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[veedubs]

Sounds like a bad starter to me.


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[brapperdoodle]

Did you figure out what originally smoked the ground? Have you put a meter on the starter to see if you lost any voltage at starter. Sorry just kind of spitballin ideas

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No, but the old 440 we had would do the same thing. I noticed on my other 550, the wire had been replaced so I think the smoking wire thing might be a "known" issue...

Sounds like a bad starter to me.


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That was my next thought, and guess what... This starter is off of the old 440 because it was a super clean OEM... I bet this starter is gunked up inside.

 

[550headache]

New starter! (IMHO)…..


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[brapperdoodle]

We have a couple new "hi-torque" starters laying around, Im gonna throw one in there and see if that helps!

 

[DAG]

There's really not many options for the circuit its got to be the Battery, Cables or Starter. I know you said the battery is fresh but perhaps try a known good one if the starter replacement does not help? you know because China. Also is the ground cable as close to the starter as possible?

 

[brapperdoodle]

There's really not many options for the circuit its got to be the Battery, Cables or Starter. I know you said the battery is fresh but perhaps try a known good one if the starter replacement does not help? you know because China. Also is the ground cable as close to the starter as possible?

Yeah the battery is for sure not it. It is a new Yuasa YTX20HL-BS, I also pulled my Superjet battery and it sounds just the same. I will check cables next, we just have some new starters so I figured i'd throw one at it

 

[smokeysevin]

Check for corrosion on the ground lug mount on the starter. Also make sure that the starter positive lug is not touching anything else. I had a ktm 390 on our FSAE car that kept burning up batteries and cables, turns out one of the "future engineers" left the insulating washer off and it was just using the starter as a battery drain resistor lol

On my 750 swap, the starter positive stud is like 1/4" off the head pipe so it could also be shorting on the pipe.

Which starter wire was smoking? From the battery to the solenoid. solenoid to starter, or both?

Sean

 

[brapperdoodle]

Check for corrosion on the ground lug mount on the starter. Also make sure that the starter positive lug is not touching anything else. I had a ktm 390 on our FSAE car that kept burning up batteries and cables, turns out one of the "future engineers" left the insulating washer off and it was just using the starter as a battery drain resistor lol

On my 750 swap, the starter positive stud is like 1/4" off the head pipe so it could also be shorting on the pipe.

Which starter wire was smoking? From the battery to the solenoid. solenoid to starter, or both?

Sean

The small 16g ground wire that goes from the e-box to the intake manifold. I removed it and replaced with a 10g wire running from the e-box directly down to the starter body. I did pull the old starter yesterday and replaced it. The exhaust gaskets ripped apart so now I have to wait for those!

 

[smokeysevin]

The small 16g ground wire that goes from the e-box to the intake manifold. I removed it and replaced with a 10g wire running from the e-box directly down to the starter body. I did pull the old starter yesterday and replaced it. The exhaust gaskets ripped apart so now I have to wait for those!

Isn't there also a big like 6 awg wire that runs from the starter directly to the battery as well?

The kawi's are setup like that.

Sean

 

[brapperdoodle]

Isn't there also a big like 6 awg wire that runs from the starter directly to the battery as well?

The kawi's are setup like that.

Sean

This one wasn't like that and neither was our old 440. However, it has a cable there now!

 

[smokeysevin]

This one wasn't like that and neither was our old 440. However, it has a cable there now!

So it runs from the starter body to the ebox or from the starter body to the battery ground?

Sean

 

[Storbeck]

Take a multimeter and measure voltage at the battery while cranking, then measure voltage at the starter while cranking. If they're much different, check various points between the battery and the starter to find out where the big jump is, that's your bad component.

If they're basically the same, then you don't have a wiring issue.

If the voltage is super low at the battery, you have a battery issue.

If the voltage is good at the starter and the starter is turning slow, then your problem is the starter or something mechanical.

What exactly "super low" and "good" voltages are, I couldn't tell you. You could check a known good setup and see what that does and compare to the one with the issue.

 

[Storbeck]

Remember you have to do this while cranking. I've had a battery that showed 12+ volts when unloaded but dropped dead when cranking. Figured it out after changing the starter relay three times because I'm an idiot.

 

[brapperdoodle]

So it runs from the starter body to the ebox or from the starter body to the battery ground?

Sean

The battery cable grounds to the e-box, same place the 16g wire grounds. I replaced the 16g wire with a 10g wire that now goes from the starter body to the e-box ground, instead of the 16g wire going from the intake manifold to the e-box ground. This is confusing but maybe you catch what im saying haha The actual battery ground cable (8g) is only about 8 inches long and goes from the battery to the ground on the e-box. The only other connection to the engine was through that old 16g wire.

I did get the new starter all bolted up and installed, the ski turns over properly now. I now have full starting power as it should! Starter was bad, but it looks so nice! The sad part is that I ripped the exhaust gaskets and now i'm waiting on those to finally fire it up haha

 

[smokeysevin]

Yep, I got it now. I was thinking that you didn't have a proper ground from the starter to the battery and that it was going through something else it shouldn't have been.

Sean

 

[brapperdoodle]

Yep, I got it now. I was thinking that you didn't have a proper ground from the starter to the battery and that it was going through something else it shouldn't have been.

Sean

Yeah, essentially the battery ground wire and the main engine ground wire are now about the same size and I believe it is a solid connection. Maybe I should have just taken a picture haha