OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines wiring question

I've just installed a new 13.5hp Intek in my 1999 cox. In typical B&S form there is no installation guide, the wanted website pages are deleted....so, I can't work out the wiring. There are 2 pairs, red & white(no plug/connector) and grey & black with plug attached. The grey is from a sensor under the carby with matching black attached the engine as an earth. The red & white come out from under the cowling.What goes where?
I've attached the starter motor lead & the heavy earth lead but am unsure what the 4 leads attached to the engine are supposed to go to - they don't correlate to the old (1999) engine. It is a 2009 model no 21B977-0160-B1.

Most likely the device under the carburetor is a water sensor, and it should be connected through the mower's wiring harness to the starter solenoid or to the engine kill switch wiring, as part of a safety circuit that may also include seat, clutch and deck height sensors. Your old engine may also have had a water detector, and this is just the new version so it should connect to the same wire as the old one. So far as wires from the cowling are concerned, there must be a kill wire somewhere, and an output wire from the generator. B&S kill wires are traditionally black, and you have not mentioned a black wire.

My guesses cannot replace proper manufacturer's information. You need the wiring diagram from the Cox workshop manual, and for the Intek engine, you need advice from an experienced B&S dealer, or at a pinch, tracing and/or testing each wire.

Below is the engine wiring spec's from the workshop manual.

thanks, that will get me closer, main problem is the mower isn't wired for a carby solenoid and I'm unsure which neg lead (there's 2)is the kill switch. Will take off the cowling & trace the leads.
redeye

i believe the solenoid in question is an anti back fire solenoid that they install to stop the flow of fuel through the carby so it does not backfire when you turn the engine off at higher rpm's. i think it should be wired through the ignition on circuit, which means that when the key is in the on position it gets 12 volts and opens the fuel jet. when power is disconnected it therefore blocks the fuel flow and eliminates any chance of backfire.
this is only from my experiences but i will have a look in my reference guides later for you if you like. i would look now only they are all in the garage.
regards jay

Jay, the device you have described is called an "anti-dieseling solenoid" in automotive circles, or an "anti-afterfire solenoid" on Bruce's first diagram. If the combustion chamber is hot enough when you switch off the ignition, some high compression emission-controlled engines can continue to run diesel-style, so just about all automotive engines post-1976 in Australia (a bit earlier in the US) have a solenoid that operates as you have said. If that is what it is, it requires 12 Volts applied whenever you want the engine to start or run, but not when you want it to stop. Bruce's second diagram shows how it would be wired. It also shows the ignition units' kill wire.

The main question to be resolved seems to be connecting the alternator output wires. The generator for the original engine may have been a DC type, with a different kind of regulator connection. This will need to be sorted out.

i've found out whats what - the red/white are red-battery charging,white is 12v a/c for headlights. The grey/black are grey-carb solenoid, and black is the kill switch.

All wired up but no go. Motor is winding over but there's no spark very frustrating, am wondering if there is a problem with the (new)engine . Running out of ideas (and patience!)

There is a good chance you either have the kill wire grounded or you don't have 12 volts on the anti-afterfire solenoid. You might try temporarily disconnecting the kill wire, and also connecting a jumper from a 12 volt source to the solenoid wire. If it works then, you can try the two things one at a time to see which was the problem.

The solenoid has 12v, tested with a test lamp, and I've tried disconnecting the kill switch, I'm at a dead end, no pun intended

You said there is no spark. If you are sure about that, the solenoid is not implicated. The problem has to be in the ignition modules and their wiring. It is unlikely both modules would be defective (unless the previous owner put 12 Volts on the kill wire at some point, of course). I suggest looking at the kill wire circuit. Can you disconnect the individual wires at the Magnetron modules without performing surgery on the wires? If you can do that temporarily it eliminates those two diodes from the circuit, ensuring that the two modules are not connected to each other. Be quite certain that what you have is an ignition failure though - you can waste a lot of time if you start off with fundamentally wrong data on the problem.

problem fixed - it had a dead coil,pretty unbelievable on a brand new engine,many thanks for the help,much appreciated - a great forum.

Thanks for letting us know, Redeye. I'll close the thread.

It is not necessarily unusual to find defective parts on a new engine unless the engine is hot-tested on the assembly line - which is done with car engines, but very few other types of engines. The theory says brand new parts often fail ("infant mortality", in the trade) then there is a long period of high reliability, followed by gradual wear-out failures. Reliability engineers call it a "bathtub curve", since the failure rate is high on the left side of the graph, low in the middle, then curves up on the right side of the graph.