1988 4.3 ltr engine starter wiring

[Rivergator]

I am having a problem with my brand new starter and I think I may have screwed up the way I wired it. The manual is not clear on what wires go where. I know the main +cable from the battery goes to the big post on top of the starter. Then there is an orange wire that looks like it is going to the alternator. There are 2 smaller posts to the right and left of the starter (arrows). To which one is this orange wire going? Then there is also a red wire coming from the 50 Amp circuit breaker and a yellow/red wire coming from the starter slave solenoid. To which posts are all of these wires going. I really appreciate your help with this. Thanks

 

[Rick Stephens]

The one on the outboard post goes to the fuel pump - purple yellow. Orange on the inboard post.

 

[Rivergator]

The one on the outboard post goes to the fuel pump - purple yellow. Orange on the inboard post.

By outboard do you mean the post to the left and by inboard the post on the right when looking at the picture. There is also a red wire coming from the circuit breaker. Where does it go? There is no electrical connection on my fuel pump. That's probably because it is a mechanical pump. I am looking at the schematic "ENGINE V6/V8 PRE-1989 MODELS". I assume that's the correct diagram for my 1988 4.3. On that diagram all the connections on the starter are too close together to actually see on which post they go.

 

[Bondo]

Ayuh,..... The big battery cable, the orange from the alternator, 'n the wire to the circuit breaker all go to the big post,.....
The yellow/ red wire goes to the small post nearest the block,.....
There should be a purple/ yellow wire on the other small post, away from the motor's block,....

 

[Bt Doctur]

Why do people take things apart without pictures? Why do people do things without a manual?

 

[Rick Stephens]

Mechanical pump = no purple/yel wire

 

[kenny nunez]

The purple/yellow “by pass” wire is connected to the “Boost” solenoid on top of the engine for the ignition + wire on the coil. Also may be connected to the outer small stud of the starter solenoid instead If the “boost” solenoid if it is a non grounded base style.

 

[Rivergator]

Thank you, Bondo, Rick and Kenny. Your posts were very helpful and gave clear answers. I am glad to say that I had the wires connected exactly the way Bondo says. When the engine didn't say a peep I thought that I goofed, but I didn't. I did some more trouble shooting and I found that the new starter is stuck, which of course I did not expect. There is no purple/yellow wire in my entire harness, which makes sense now, since I have a mechanical fuel pump. Rick and Kenny explained that. I also looked at the old starter and the left small post (looking at the picture) has never been used. It is totally rusty and no nut could have ever been on it. So Bt Doctur, to answer your flippant, condescending "waste of time" questions, I did write down the wiring but thought that I may have made a mistake and wanted assurance that I didn't. Taking a picture of the starter is of little use, not gonna see much and if you had read and paid attention to my post #1 and #3 you would have known that I have all the manuals and documentation pertaining to my boat, year, motor, outdrive and peripherals. Now I need to see how to get that starter off the engine down there in the bilge, tricky job! Thanks for all the good advise.

 

[Rick Stephens]

Now I need to see how to get that starter off the engine down there in the bilge, tricky job! Thanks for all the good advise.

Hah! Need a pet monkey.

 

[Rivergator]

Here are the pin outs for a Mercruiser 4.3 ltr starter. This will come in handy for the ones who want to know. To confirm, the yellow/red wire which comes from the slave (boost) solenoid will go to the right small post and nothing will go to the bottom post. The top post will be wired the way Bondo said it would. And the purple/yellow wire does not exist because my engine has a mechanical fuel pump and therefore the left small post is unused. Have I got this right now?

 

[poconojoe]

Why do people take things apart without pictures? Why do people do things without a manual?

Yeah, I don't get that either, especially since pictures are instant and you can take a bunch of them, unlike when we had to wait for the film to get developed.

 

[Rivergator]

All the wiring questions I had are not the problem. The way the starter was wired was correct. I dread the thought of having to remove the starter from the motor which is virtually impossible with the engine in the boat, but I am sure some wizkid has come up with a trick to do it. My assumption is that the starter is frozen or may have an electrical problem even so it has never cranked to engine one turn. It's been sitting installed on the engine for almost a year, so it shouldn't be frozen. When I turn the ignition to start I can hear the starter solenoid kick the gear out, but that's it. No cranking. The battery is full 12.45 V. Is there a way to test just the starter bypassing everything else on the boat? I want to make absolutely sure that the starter is the problem before I yank the engine. Any advise is highly appreciated. Thanks

 

[Bt Doctur]

Remove the exaust manifold, then you gain access to the starter wiring and bolts

 

[Rick Stephens]

Is it possible the engine is frozen or hydrlocked? Or the drive?

Note, the starter already bypasses everything else.

 

[dubs283]

All the wiring questions I had are not the problem. The way the starter was wired was correct.

The title of this thread would suggest otherwise

Is there a way to test just the starter bypassing everything else on the boat?

Pull the spark plugs out and remove the drive. Have you tried rapping on the starter itself to see if it's stuck?

 

[Lou C]

Here are the pin outs for a Mercruiser 4.3 ltr starter. This will come in handy for the ones who want to know. To confirm, the yellow/red wire which comes from the slave (boost) solenoid will go to the right small post and nothing will go to the bottom post. The top post will be wired the way Bondo said it would. And the purple/yellow wire does not exist because my engine has a mechanical fuel pump and therefore the left small post is unused. Have I got this right now?

My engine (mechanical pump) has the purple wire on that small stud on the outboard side but mine is a points ignition not electronic, maybe that makes the difference.
If you want a good quality starter get an ARCO, I have their starter and alternator on my engine and both work 100% all the time.

not mine but I labeled this pic.....
the orange wire from the alternator also goes to the top connection (one labeled from battery)


on my boat I can get the starter out simply by removing the rear seat on that side, the wood bulkheads and then the battery. Don't have to remove the exhaust manifold. The old Delco direct drive starters were a pain to install, very heavy, the newer PMGR ones are a pleasure, half the weight and spin the engine much faster.

 

[Rivergator]

The engine was put back in the boat 3 weeks ago after being rebuilt. It has no manifolds, no plugs, no hydrolocks, no drive. I should have started a new thread asking "How to test this starter" and starter only, bypassing all solenoids, wirings, ignition key etc. At first I thought I had a wiring problem which was debunked but since this still is the unresolved problem I thought I continue with this thread assuming that the entire thread is read by potential posters. Sorry for the confusion I may have created here, but at this point my question really is "How do I test this starter on the engine in the boat bypassing everything else. I want to make sure that the starter turns without engaging the starter gear"

 

[Rick Stephens]

I'm guessing this motor was rebuilt but not test run before installing.

 

[Rivergator]

I'm guessing this motor was rebuilt but not test run before installing.

No Rick, the motor was not test run before installing. It was installed to be test run. I rebuilt the motor myself (see my post "Overhauling my 1988 Alpha One Drive Train"). Maybe a machine shop has the facility to put engines on a test stand but the average dude like me has to do things one step at a time. I admit I should have tried at least to crank the engine a few turns by attaching a battery to the starter, but as is evident by my thread here I am not sure how to do that without a harness installed and using my ignition key. Rick, I gather that you are a very knowledgeable person when it comes to Mercruiser but I am truly surprised that you didn't just answer my simple question unless you are like me and don't have a clue what posts on the starter to touch to make it spin, just spin.

 

[Rick Stephens]

I fired my 4.3L up sitting on blocks of wood and with a 1 gal gas can, a garden hose to the thermostat housing, and a battery with jumpers. It is so easy as to be ridiculously simple. And is so much better than checking your work after it's in the boat. In fact the reason I mentioned it, still may be most useful to pull the motor and do that with yours.

To spin the motor, disconnect the one wire going from solenoid to electric motor - says 'Field Lug' in your diagram, and just power that lug or wire that comes out of said electric motor.

And no, I am not a Mercruiser expert. I own a welding and fabrication shop. Just finished wiring a homemade 3 phase converter to run a new lathe. You can do anything if you spend the time reading up and understanding it. And don't mind getting dirty.