Mercruiser 470 help please

Trackertrucker

Seaman Apprentice
Joined
Jun 18, 2015
Messages
33
Hi all, thanks for letting me join. I'm not new to boating however I am new to owning an I/O. I have a 1977 Sea Star with a mercruiser 470 in it. It runs great and I think it has been well taken care of. However I went to start it today and the starter seemed to really drag even with a good battery on it. I eventually gave up on it for the day when it would barely try to crank. I'm thinking the starter is shot as I jumped across the solenoid and got the same result also jumped straight from battery to the starter with the same results. My question is can a newer model 470 starter with the solenoid built into it be used on my 1977?? Thanks
 
Joined
Mar 27, 2010
Messages
3,008
It could also be the negative cable needing cleaning, unless you also jumped that over as well off the battery in your test.

I have the '89 version of your engine, the block is the same and the newer starter would bolt right in.

My starter has the solenoid on it, it's part number is Mercury #
97499A 2

Check around your area, maybe you have a rebuild shop that can rebuild yours or they may even have the newer style your looking for.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Yeah on those older starters the armature shafts had a tendency to bend and the windings would rub against the field coils causing a drag. A new modern starter will work fine. I went with a PMGR starter and it works great. You would only need to run a new heavy red wire from the battery + to the large terminal on the starter selonoid and a wire from the solenoid in the block to the starter solenoid. A smaller (12 ga) wire would work fine. Here is the starter I am talking about: http://www.ebay.com/itm/New-PMGR-St...170-180-190-215-250-270-325-390-/141476565486
 
Last edited:

Trackertrucker

Seaman Apprentice
Joined
Jun 18, 2015
Messages
33
Awesome. Sounds like I will be back in business soon, think I will double check wiring and connections and if not I will be ordering a new starter thanks for the help!
 

gregorious

Cadet
Joined
Jul 7, 2014
Messages
14
I have a 485 mercruiser engine and thought my styarter was bad too,nobody had a new one and since the solenoid was seperate could not upgrade to a new style so got it rebuilt
 

e5earley

Cadet
Joined
Mar 29, 2015
Messages
25
I have a 1980 Chaparral with the 470. I changed over to the newer style starter with built-in solenoid. I did have to shorten the starter mounting bolts to make it work. You will also need to do a little rewiring to incorporate a slave solenoid.

Even with the new starter it would drag a bit until I used some emory cloth on the battery cables. Turns over great now.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Little info here: The slave solenoid on the block of my "new" 470 engine is exactly the same as the solenoid as used in the older engines with the starter without the solenoid. The only difference is that on mine that solenoid activates the starter solenoid, whereas on the "old" setup the solenoid supplied voltage directly to the starter motor. The new starters will work fine in place of the older starters (and are much more efficient, and way smaller). All you have to do is wire up the solenoid to activate the new starter solenoid. The design of the older 470's is the reason that on 470's the coil resistance wire is bypassed by getting voltage from the slave solenoid rather than from the starter solenoid as on a 3.0. Hope this helps a little.
 

Trackertrucker

Seaman Apprentice
Joined
Jun 18, 2015
Messages
33
Thanks for all the information, one last question Terry, if I buy the starter you listed on eBay does it come with a wiring schematic or is there something here someone could post?
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Maybe? It is pretty easy though. you will want, to fabricate one new wire, and need a new heavy red battery cable. Right now you probably have a heavy red cable going from the selonoid to your starter. That wire is way heavier than you need, so you will want replace it. On the starter selonoid there are two ( maybe 3) terminals, a large terminal and a small terminal ( should be labeled "s"). So, first thing REMOVE THE NEGATIVE (BLACK) CABLE FROM THE BATERY. Install the new starter. Make up a 12ga red wire that will go from the selonoid on the block to the start terminal on the starter. Measure and get a new red battery cable that will go from the battery + to the large battery terminal on the starter. Tighten everything down, and reconnect the battery neg, and you should be good to go. Now I don't know exactly how you are set up presently, so you probably already. Have a heavy wire on the battery +, so you may have to figure out how to attach the starter battery wire. There are some wing nut type connectors that may work. Good luck!
 
Last edited:

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,023
Just for funsies, pull your plugs and give it another shot. The 470's occasionally like to leak into the 3 and 4 cylinders and hydrolock. If you pull the plugs and see a geyser out of your cylinders when it cranks...
 

Trackertrucker

Seaman Apprentice
Joined
Jun 18, 2015
Messages
33
i took the starter off and disasembled and cleaned it, was full of rust. worked great with no load on it however put it back on the boat and it worked a little better but still not cranking as fast as it should. I ordered the new starter off Ebay this morning that Terry suggested. will keep you posted. Thanks
 

Trackertrucker

Seaman Apprentice
Joined
Jun 18, 2015
Messages
33
Got my new starter yesterday, put it on, wired up and now it cranks over like it should. Thanks for all the help
 
Top