D'oh! My -6 won't start..., Some help for the check writer please... Options

[smj]

So a month or two ago I went four or maybe six weeks without running the 3.0l SC motor in my 914-6. I had been firing it up every other weekend, but things happened.... Anyway, no joy regardless of where the hand throttle sits. Every now and again it taunts me by sounding as if it fired on one revolution.

The motor is carbed, not fuel injected. Plenty of juice in the battery, the starter motor is happy to turn, there's gas in the tank. I know I need fuel, air, and spark -- the question is how to check that these things are getting to where they need to go. I feel a thrumming in the engine bay fuel lines when the key is in the right position, and I can hear the fuel pump running.

How do I confirm that I'm getting a pulse to the spark plugs without a clamp-type electrical meter?

Links to tutorials would be welcome. I did try a couple of searches before posting, but the keywords I used must've been way too broad...

Thanks,
--Steve.

[rfuerst911sc]

Are you only useing the hand throttle when trying to start? Or are you giving the throttle pedal a "pump" to the floor to squirt fuel into the engine and then setting the hand throttle? I'm thinking if the car has sat for 6 weeks and if your only useing the hand throttle your not getting enough fuel to start the engine. To check spark remove the easiest to reach spark plug then reconnect the removed plug to the wire. Hold the spark end close to the engine and have someone turn the starter motor on you should see spark at the spark plug end.Good luck.

[Joe Bob]

Give some pumps....and/or a shot of ether in the carbs while cranking.

You check spark by pulling a plug wire and plugging in a spare plug and cranking near a ground....

[ClayPerrine]

Here is the trouble shooting process I use.


Take the air cleaners off. Look down the bores of carbs. Rapidly open the throttle. You should see a stream of gas out of the accelerator pump jets.

If you do, then pull the coil wire and lay it up against the fan housing. Crank the motor and see if you get a spark. If you don't, check the points/electronic ignition box. IF you do pull a wire from a plug and check it for spark the same way you did the coil wire (remember to plug the coil wire back in)


IF you don't get gas from the accelerator pump, then you have a carb problem. IF it has been sitting for a while, it is probably the carbs. Check all 6 bores for the accelerator pump spray. If you get some that have it and some that don't, start looking closely at the carb that doesn't. If none of them have it, check the fuel feed. It may be clogged up, or the pump is not working. Pull the feed line to the carb, put the line in a jar, and turn the key on. Make sure the jar fills with gas.


I also like Mikey's idea of giving it some fuel to try and fire. But I use propane from a handheld torch, not ether.

[Eric_Shea]

Clay... you forgot to say "Carbs suck, that's why I have MFI!" (IMG:style_emoticons/default/biggrin.gif)

Steve, when an engine like that sits you may need to get fuel into the bowls again. Run the pump, then pump the gas pedal as mentioned before. Sometimes 10-15 pumps on the pedal before it knows what you're trying to do. That's the first and simple approach.

Then follow Clays, "look down the carb" route.

Then follow Clays"check your spark" method but your comment regarding the taunting means to me, you've got some spark... maybe not enough fuel.

[smj]

I'd been hesitant to feed too much gas in so I was giving it no more than a couple pumps. I do believe I hear fuel moving when I manually twiddle the throttle in the engine bay, and I have some starter fluid around for the bike. I'll give the fuel suggestions a shot, then move on to spark.

If I were to spray ether into the carb, wouldn't I want the hand throttle in the normal/running position in order to pull in more of the ether?

Thanks!! I'll give it another shot shortly.

[Eric_Shea]

Well... I'd say if you've been hesitant about giving it fuel and not more than a couple pumps; there's your problem. (IMG:style_emoticons/default/wink.gif)

[ClayPerrine]

Clay... you forgot to say "Carbs suck, that's why I have MFI!" (IMG:style_emoticons/default/biggrin.gif)

DAMN!!! I knew I forgot to post something...... (IMG:style_emoticons/default/laugh.gif)


Actually, the MFI is worse for cold starting. Open the throttle to about half, hold it with the hand throttle, and crank the motor. Then crank the motor some more. Then crank the motor some more and it will finally cough and spit it's way to life. Then sit there for a minute until all 6 start to hit and it smooths out.

As the engine warms up, slowly lower the hand throttle to keep the engine speed around 2K. Then after about 3 or 4 minutes, you will get a smooth idle.


But after it's warmed up.... WOOOHOOO!!!!!! (IMG:style_emoticons/default/w00t.gif) (IMG:style_emoticons/default/w00t.gif)

[rick 918-S]

It's not going to start. You need to give up and send it to me with the title and registration. (IMG:style_emoticons/default/biggrin.gif)

[smj]

Summary: Today it turned over. No real explanation, but it worked.

I'd tried most of what was suggested in this thread, and had gotten to the point of going to Kragen and buying a spark plug specifically to check for spark w/o trying to remove one of the installed plugs. And then for a couple weeks I just didn't want to deal with it.

Today, worrying that if I let it sit much longer without even cranking the motor Bad Things would start to happen, I gave the -6 another try. For the second attempt I put the hand throttle all the way down -- and it stumbled after a couple revs. Hmmm... Tried it again, nothing. Started slowly raising the hand throttle, cranking, raising a little more, trying. On the third or fourth attempt, it caught and ran on it's own, anemicly, for a little bit. Hmmm...

Well, eventually I got it to fire and run. And in the process I filled the garage with the most godawful stench and grey smoke you'd ever want to behold! (IMG:style_emoticons/default/icon8.gif) I'm sure the neighbors love me, whooping and hollering while a foul-smelling cloud wafts out over their houses... By the by, the fluid trickling out of the tailpipe was greyish -- hard to say what if anything it smelled like,given what else was in the air at the time.

Anyway, the car smoked like a Navy destroyer laying down cover, but it didn't sound too bad so after spreading my smokey idea of joy through the neighborhood for a while I took to the highway to try and get everything warmed up properly. That tailshifter's still a pain in the ass, but the car felt pretty good otherwise and I think by the end the only smoke was the usual problem I have with condensate from the oil tank filter/breather widget dripping down onto the exhaust.

Just wanted to close out this particular episode, and again thank everybody for their help. Hopefully nobody's reported me to the DMV as a result of tonight's adventure.

Now, do I rebuild this lump or replace it with something that's got EFI...

--S.

[sww914]

These cars don't like vacations.
You need to drive it around more.

[smj]

These cars don't like vacations.
You need to drive it around more.

Well, I'd love to log more time on it. Several factors interfere, not the least of which is a silver 914-4 in good shape... Maybe this is the big reason to get rid of the -4 -- it's distracting me from making progress on the -6.

Before this incident with not starting, the lump already smoked a fair bit when warming up. It's in need of a rebuild, there's so much compression getting past the rings to the crankcase that it pukes oil into the engine bay through the oil tank breather if you stomp on the pedal. This is why I was only taking it out every weekend or other for a half hour.

Hrm. I like driving the -4 an awful lot, but maybe it's time...