Starter Motor on 8.1S refuses to spin??

[Jimmy Buoy]

I've had an issue with my Stbd engine's starter motor. Not always, but sometimes when I go to start the engines it won't turn over (starter motor won't engage). :huh:

After pressing the ignition switch to the first detent, you hear the "beep" and the buzz of the fuel pump pressuring up and then stop, the volt gauge shows 12.5Vt, then I press the switch the rest of the way down to engage the starter motor - but I only hear a "click". The volt gauge drops to about 10V while the starter button is depressed as well.

I've played with the gear selector just in case the cut-off switch on the tranny is out of adjustment (as it is on the port engine) without any success.

Eventually, after repeating the process (sometimes once, other times 4 or 5 times) it turns over and fires up. It seems to happen more when away from the dock which leads me to believe part of the problem is battery power. I've checked each cell on the two batteries providing power to this engine and they are "border line" between the good and fair markings and all cells are quite equal.

A mechanic said it could be corrosion on the starter's amature due to exposure to salt water (he's a salt water fear-monger though) and the starter might have to be replaced.

It's always a crap shoot after drifting for a while whether or not I'll have problems starting this engine. Just when I think it will be a big deal, it starts on the first try! I'm looking for it to just work "right".

With 300 Hrs on this 2001 - is this likely to be a shot starter motor?? :wow:

 

[douglee25]

Check your connections and make sure they are all good and tight (batteries, starter, switches, etc). Your remote solenoid may be on the fritz.

Doug

 

[osd9]

Have you tried using the dash mounted 'emergency start' battery combiner?

 

[Jimmy Buoy]

I'm planning on installing new batteries in the spring and will ensure that all connections including at the starter motor are good and clean/tight. Where is this "remote solenoid"? Is it part of the starter motor itself??

Regarding the batter combiner - yes, I have tried that and it has made no apparent difference. Is the combiner just a relay that connects the two battery banks (starboard/port) together?

 

[rondds]

Could be the starter solenoid. I had both mine go within a few months of each other. If you put 12 volts directly from the battery to the starter motor and it spins, it's not your starter and it's probably the solenoid, assuming your neutral cutoff switch is indeed not the problem. There is also a way to jump the solenoid but I dont know which terminals to jump (a voltmeter would tell you).

PROBLEM!!!!! spark produced by this "jump" could be a serious issue. I do NOT recommend you do this. (I have, but I'm not suggesting you do it).

 

[RollerCoastr]

I also vote solonoid. I had the exact symptoms last spring. Fuse was good. Pulled the starter off and gave it 12V on the bench, and the motor spun perfectly.

I traded it as a core for a rebuild plus ".15 Boat Bucks" ($150) and was back in business.

There was some confusion for a while because GM and Mercury don't seem to agree on the definition of RH vs. LH rotation. The tech scrape some paint off and found a sticker that contradicted the Merc label.

 

[carterchapman]

I also vote solonoid. I had the exact symptoms last spring. Fuse was good. Pulled the starter off and gave it 12V on the bench, and the motor spun perfectly.

I traded it as a core for a rebuild plus ".15 Boat Bucks" ($150) and was back in business.

There was some confusion for a while because GM and Mercury don't seem to agree on the definition of RH vs. LH rotation. The tech scrape some paint off and found a sticker that contradicted the Merc label.

Did you buy a Mercruiser starter or a GM (auto) starter? What was the price difference?

 

[mawyatt]

Jim,

If I understand you this is only a problem with one engine. If so, you could swap the battery connections (only need to move the + cable) and see if the engine starts without issue with the other battery. If it starts Ok then I would suspect the battery, you could confirm this if the other engine has an issue starting with the suspect battery.

 

[mistercomputerman]

Some of the big block GMs have an "exciter" wire on the solenoid that is a push-on connection to one of the screw posts on the solenoid.

Might see if yours has one and make sure it is tight. I know there is one on the 7.4 but I am not sure about the 8.x motors.

 

[rondds]

I would suspect the battery

I think we could rule out a battery issue since the battery emergency start switch didnt get it cranking.

 

[mmcguire2002]

Silly question, but are you sure it is completley in nuetral? If it is not, you will hear the fuel pump, but the starter motor will not engage until it is out of gear.

 

[Southpaw II]

I've had the same problem....and I suspect it's the push button starter switch on the dash. Only thing I would add is that it seems to start quicker after it has run for a bit and warmed up. When it cranks, it spins quickly like there's no prob. My problem starter is port, and I wondered if someone has stepped on the starter when climbing down into the ER, loosening a connection.

 

[Dirtguy]

Same batts start the port engine but not the starboard.
You hear clicking and the voltage goes down to 10.5 while pressing the start button.

Sorry but I'm going to buck the trend and say that it's from the solenoid to the motor. Maybe a loose cable from the solenoid to the motor, or a bad starter motor itself. The volt drop is the item that makes me wonder.

dg

Keep us posted!

 

[Jimmy Buoy]

"Silly question, but are you sure it is completley in nuetral? If it is not, you will hear the fuel pump, but the starter motor will not engage until it is out of gear."

Not a silly question - I know what you're talking about, moving the shifter to various "neutral" positions while holding the starter switch down and it doesn't react like the port engine. The port engine can also be stubborn to start, so if the starter switch is held down while moving the port shifter back and forth a bit it will catch the neutral "sweet spot" and engage the starter motor.

The Starboard engine will not start by moving the Starboard shift lever while holding down the starter switch. At first it seemed to be the case, but it either engages the starter as soon as the starter button is depressed or it doesn't. There is never a point when it engages AFTER the button is held down while adjusting the shift lever(unlike the Port starter). I can try multiple times without success, than the next attempt engages the starter motor.

It's harder to diagnose when it doesn't act up consistently - but I like a challenge!

" I've had the same problem....and I suspect it's the push button starter switch on the dash. Only thing I would add is that it seems to start quicker after it has run for a bit and warmed up."

Regarding this comment, it is similar to mine since it happens less often if I try and restart the engine right after shutting it down. After its off for more than 20 minutes or so, it's back to problems engaging the starter.

Thanks everyone for pointing giving me ideas of how to trouble shoot this problem. Although spring is months away, I can still do some cleaning and testing when in storage. I'll let you know what I find...
__________________

 

[Newbie]

I had the exact same problem as you when I surveyed my current 340 w/ 8.1's. Being still under warranty, I let MM chase the problem. They replaced the starter solenoid and I have never again had the problem.

After ruling out battery's themselves and loose connections, start with the solenoid. I'd put money on it that its your problem.
SB

 

[Jimmy Buoy]

Well I'm back - and so is the problem...

Here's what I've done so far,

1. Replaced both batteries that start the Stb Engine - still have the problem (yes I did clean the cables and posts before installing)
2. Swapped starter motors between engines, cleaned all disconnected wires before reinstalling - still have the problem with Stb engine ONLY (rules out a bad starter since I have yet to have the problem with Port engine)
3. Removed/tested/reinstalled slave solenoid by applying power to smaller posts and checking larger two posts for continuity, seems to work just fine every time - still have the problem.
4. Tested starter switch by removing yellow/red power wire (that powers the slave solenoid upon starting), showed full power when starter button depressed every time - still have the problem.
5. Tested yellow/red power wire connected at the starter by disconnecting it then testing for 12vt upon depressing the starter button, works every time - still have the problem.

Things to still try - Remove all ground wires from post on the block, clean and reinstall? Swap slave solenoid with other engine?

Any suggestions??:huh:

 

[sprink56]

JESUS.....I have had the exact same problem from time to time and there seems to be no consistancy to it. I was beginning to think that it was heat issue and the starter was on it's way out. I pulled the starter and had it tested and it was fine. I have not had the problem since I re-installed the starter. BTW all of my connections were tight....mine was starboard side also.:huh:

 

[Southpaw II]

Jim,

Since my last post, I changed out the slave solenoid, but it didn't solve the problem. My prob is still intermittent with the port engine. When I push the switch to the first detent, and the fuel pump starts, I see a slight voltage drop on the gauge. When the pump stops, I see it climb back to about +/- 13 volts. Starting at this point seems to depend on what that voltage is....around 13 or better, it starts right up. A little bit lower, and it doesn't. Sometimes if I just hold the start button down, it will engage the starter after about 5-10 seconds.

Just passing on info here.....still haven't figured it out.

 

[dc380]

At this point I would switch the port and starboard helm switches. I would also look for a loose or corroded connection at the helm.

I had a similar issue on my last boat, and it was the connection to the switch.

 

[Southpaw II]

At this point I would switch the port and starboard helm switches. I would also look for a loose or corroded connection at the helm.

I had a similar issue on my last boat, and it was the connection to the switch.

This sounds like the best next step for me...will report back.