QuestionQUESTION: I have a Troy Bilt Walk Behind Lawn Mower with a B&S 7HP Intek Engine with Electric Start feature. It will start if I pull start it but not with the electric start.
Starter spins up, gear moves up spindle on starter and engages flywheel and spins the flywheel. Spark tester shows a good spark.
replaced the plug anyway and gaped to .020" (per B&S spec). Later gaped at 0.025".
It won't start.
Tug on rope handle 3 or 4 times and it starts....
Shut off and then try to re-start with electric start and again, it won't start.
B&S Model Number: 127607-0369-E1
In spite of good manual start and good spark, changed air filter and filled with new gas. Oil level is good. Battery is good (approx. 12.7 vdc), holds charge and I don't hold ignition on for more than a minute so as not to burn up starter. Again, in spite of good manual start and a good spark, I checked gap between ignition module and flywheel and this is within spec.
Any ideas?
Thanks, John.
ANSWER: There is a switch on the engine that connects to the engine shut-off cable and starter system. Are the wires connected?
Are you sure you have spark with the electric starter when cranking the engine? If so, then there must be a carb problem but this contradicts itself when the engine starts with the rope starter.
Does the electric starter turn/spin the engine when the spark plug is installed?
Eric
---------- FOLLOW-UP ----------
QUESTION: Hello Eric-
Thanks for getting back to me.
To answer your questions:
1. Yes, the wires are connected to the switch and it is functional. I tested it in the beginning by disconnecting it and the starter wouldn't start when the key was turned on. Sorry...should've mentioned this before.
2. Yes, I have a spark when using the electric starter to crank the engine. I put a spark tester in series between the plug and the plug wire from the ignition module to confirm this. I then left the tester in the circuit when pull starting the engine just to compare what I was seeing with the tester..No observable difference. Since the mower is 5 years old and still has the original battery, I thought that perhaps it wasn't spinning the starter fast enough to generate a spark (B&S specs says that the flywheel must spin at least 240rpm to generate a spark) but it is and I do get the spark. I even checked the magnets on the flywheel to make sure that they were good and re-set the gap between the flywheel and the ignition module.....Result: a good spark with the electric starter.
3. Yes, the electric starter turns/ spins the engine with the spark plug installed.
This has bugged the hell out of me and I went back and got it from the little old Lady that I am trying to help by working on this thing. And this is what I discovered today....you are correct, it does appear to be a carb problem. B&S specs for this engine say to press the primer bulb 5 times. Well, just for grins, I pressed it 8 times and after a few turns of the key, the beast started! It belched out a shitload of black smoke but ran just fine. I shut it off, did a manual pull start without priming (it was just running) and after two pulls, it started. Then I shut if off again and tried the electric start and it wouldn't start! So I "primed" it again and after a few turns of the key (again) it started up...same shitload of black smoke but it started.
This appears to be an "automatic carb", with no manual choke and there is no engine speed adjustment control..only a speed adjustment for the drive wheels.
Perhaps I need to do a carb tune up....what do you think?
Thanks for taking the time on this with me.
John
AnswerI would start by cleaning the carb. You mentioned you have a primer bulb, which is a better design IMO, than the auto-choke they have started using. I have an electric start on an auto-choke Briggs and it works ok when the engine is cold but when the engine is warm the electric start does not function very well. I suspect the starter is not spinning the flywheel fast enough to help open the choke when the engine is warm leading to too much fuel causing a rich fuel mix.
I'd clean the carb but a couple of extra pushes on the primer bulb will not hurt anything.
Eric
