Wrong starter? Engine turns over SLOW

[jze1212]

I recently picked up a 24' aft cab Invader, with a Mercruiser 5.7 I/O. I bought it with the assumption that I may have to replace the engine. But I'd like to see if I can get this one going. The engine looks like it has a new starter but it turns over slowly, as if the starter were geared wrong, like a creeper gear.. Strange. Sounds the same with spark plugs in or out. Sounds like the starter is working hard and cranking over yet the motor is not turning over fast. I am going to pull the starter and put a good one in, not til next week.. I thought I would ask anyone if they have come across this? The battery has a full charge. I did a compression test, only on the left bank of cylinders so far, compression is low across the board but fairly even. I am not convinced those results are accurate though based on how slow the engine turns over, and I heard that the lifters may not be pressurized due to sitting around. Is it also possible that it could be a starter for a left rotation engine?

 

[chiefalen]

Re: Wrong starter? Engine turns over SLOW

Pull the drive, and clean all the connections, don't forget the ground at the motor.

Spray pb blaster in all the spark plug holes, pull the valve covers, spray blaster all over everything there also.

Turn the starter, a little and do it all over again. Got it pb blasted good 2-3 times, put the plugs back in.

No drive on the boat try it now.

Post the result.

 

[Bondo]

Re: Wrong starter? Engine turns over SLOW

as if the starter were geared wrong

Ayuh,....

That Ain't the Problem,....

As noted by Chief,... Pull the drive so you're working on the Motor Only...
Then make sure the wiring is Up to Stuff...

I suspect your 1st thought is Right,... The motor sounds Beat...

 

[JustJason]

Re: Wrong starter? Engine turns over SLOW

before you go through the trouble of removing the drive.... get a digital multimeter and do a voltage drop test across the entire starting system.

 

[jze1212]

Re: Wrong starter? Engine turns over SLOW

Thanks for all of the replies... They all make sense but if you heard the way it is turning over it sounds like the starter is physically spinning as fast as it can and the motor is not turning over fast. Not the same as the result of the drive being attached and being possibly engaged ( if that makes sense..) The drive will have to come off sooner or later so maybe sooner THAN later, haha. Does anyone agree that I would not get an accurate compression test if motor is not turning over fast? Or close to fast... Keep the replies coming , thanks!!!

 

[J JACKSON]

Re: Wrong starter? Engine turns over SLOW

you may as well pull the drive its only six bolts then try it. sounds like you could have a drive locking up or maybe a bearing spun in the engine but i would pull the drive first. at any rate even if you fix the engine it still needs to come off to do the impeller, check alignment etc.

 

[JustJason]

Re: Wrong starter? Engine turns over SLOW

trust me.... read this.

http://us.fluke.com/usen/apps/FlukePlus/ArticleCategories/Automotive/Diagnose+Volt+Drop.htm

 

[chiefalen]

Re: Wrong starter? Engine turns over SLOW

Yes Jason is correct could be the voltage.

But when someone trys turning over a motor on a boat that sat for a while, and it's slow cranking, why not pull the drive next.

After removing the plugs spraying the cylinders, and the rockers, trying to turn it over again, and again, your liable to burn out the starter that was perfectly good.

Pull the drive has to come off anyway.

Then like Bond-o says Your only working on the motor.

When you do pull the drive you might be surprised how rusted it is in there.

 

[9533Zero]

Re: Wrong starter? Engine turns over SLOW

I just looked into finding the correct starter for my 86 3.0 and was told that there is a difference between the number of teeth on the original starter and the new ones for that engine. Old ones had 9 teeth on the gear. New ones have 11 teeth. The result is the engine will turn slower when the starter is engaged b/c of the different gear ratio. Could thye poster have the wrong starter on the motor? Has anyone ever heard of this or offer an explanation on why the change was made? The source was a local marine machine shop and i have no other reason to doubt what they say.

 

[Bondo]

Re: Wrong starter? Engine turns over SLOW

Could thye poster have the wrong starter on the motor?

Nope,....

Chevy starters come in 2 basic flavors,...
The Straight Accross bolt pattern,+ the Staggered bolt pattern....

If it bolts On,... It'll Work....
Regardless of the tooth count of the bendix,.. It'll spin the motor Fast enough to start....

 

[chiefalen]

Re: Wrong starter? Engine turns over SLOW

The newer starters also take less juice to turn, plus have gear reduction.

The teeth have nothing to do with it. Allow me to ask a question of you??

You have a front bracket on that starter??

It tight the bolts? Grab that starter is it tight up on the block, or loose??

 

[JustJason]

Re: Wrong starter? Engine turns over SLOW

But when someone trys turning over a motor on a boat that sat for a while, and it's slow cranking, why not pull the drive next.

Because after you know how to do it, it takes all of 5 minutes to check the starting system.... and you don't need a gasket kit.
I'm not saying it's not a good idea to pull the drive. But by pulling the drive you may be just masking a starter issue.
I get 50 people every year that ask me why their boat cranks slow, and I tell them the same thing.... that motor should crank over just as fast as the engine in their car. I can't even tell you how many cables I replace every year.
On a side note...... if you've been running an engine with bad cables for a while it's not uncommon to have to replace the starter. That starter is screaming for current once the voltage drops even a little bit.
Step 1 would be to do a voltage drop test and replace what you find along the way.
Step 2 would be to measure the current when the starter is cranking.... it should be 150-175ish amps....

 

[9533Zero]

Re: Wrong starter? Engine turns over SLOW

Not trying to hi-jac this thread, but thanks Chiefalen and Bon-o for the answers to my "teeth" question.

 

[chiefalen]

Re: Wrong starter? Engine turns over SLOW

Zero please start your own thread next time so more people see it.

And your welcome.

 

[chiefalen]

Re: Wrong starter? Engine turns over SLOW

To your compression question. Compression numbers won't be accurate unless the motor is warm. And oil had a chance to circulate.

 

[jze1212]

Re: Wrong starter? Engine turns over SLOW

Thanks again for all of the replies. I put a couple of quarts of Mystery oil into the motor and cranked it, really no difference.. I have not been able to do much more than that though, Not sure if any of you are New Englanders but I am in Mystic CT and man it has been a nasty winter! I am going to try to get out there this weekend and get back to it.. I don't think the drive will be coming off until the spring but I will check the cables and the voltage.. I'd like to get this thing cranking over so I can get an accurate compression test.

 

[legoman67]

Re: Wrong starter? Engine turns over SLOW

have you tried hotwiring it and bypassing the solinoid on the engine, i know we had the same problem, turns out the solidnoid on the engine is bad, i jumped the solinoid on the starter with 12 volts(to open it) and it turns over and starts fine now.

 

[krisnowicki]

Re: Wrong starter? Engine turns over SLOW

how low is low on the compression test? Chief is right unless the engine is warm you won't have reliable numbers. I had a problem with voltage drop on my old 350. It caused the starter to do alot of haywire and slow things. Ultimately I left it unattended long enough and it ending up costing me alot more money. If you just bought a boast you should pull the drive and check everything any ways. But, If it were me I would do the drop test first to make sure. It will only take 20 mins and once its done you know its not the problem.

Both new starters I went threw had warnings on them that said operating this starter with lower the nessicary voltage will ruin the starter and it did......

 

[jze1212]

Re: Wrong starter? Engine turns over SLOW

I only checked one bank, on the port side.. It was low, 40-60 psi.. I have not checked it since I dumped mystery oil in and cranked it a bit though.. Next time I get out there I am actually going to feed some mystery oil directly in through the spark plug hole. I don't know that the oil pump is doing it's job or not so I'd like to know for a fact the oil is getting to the cylinders. Then you have to worry if the lifters are working without oil pressure right? I guess I find it hard to believe that all the cylinders on one side would have problems? Usually isnt it just one or two bad seeds?

 

[Bondo]

Re: Wrong starter? Engine turns over SLOW

I bought it with the assumption that I may have to replace the engine.

Ayuh,....

Donno what to tell ya,....

Pull it,+ Tear it down,... The Answers await you.....