Engine wont start after removing carb

[Silvertip]

Re: Engine wont start after removing carb

Lets go back several responses where you said you saw a puddle of fuel seeping passed the throttle plates. When you have someone pump the throttle, there should be two distinct spray streams as you look into the carb. If not, there is also an accelerator pump problem. Next you said you would adjust the screw to make sure the choke was closed. That is also wrong. That screw rides on a stepped cam and controls idle speed during warm up. It does not adjust choke position. The choke is adjusted on a STONE COLD engine. Open the throttle, move the cam to the lowest step, and adjust the choke disk so the choke plate just barely closes. That's all there is to it. And lastly, why is it you want to immediately jump to the most expensive item iin the ignition system for testing. Test the coil first. It's easy and if it needs replacement, its inexpensive.

 

[JeremyL]

Re: Engine wont start after removing carb

I had the Carb off again on Sunday, thinking the floats may have been stuck. I got the gas out of the bowls by tilting the carb to the side, and after that i could hear the floats moving freely inside the carb. After putting the carb back on, it quickly filled with gas after cranking, and I only checked to see if gas was getting to the throttle plates with cranking the engine for testing. I will go out and make certain that gas comes out as two distint sprays while pumping the throttle for my next test.

Starter fluid/Gas down the carb throat does not change behavior, which is also why I'm starting to favor the idea of a weak spark.

This is probably important: the carb was leaking gas at the gasket when I was doing a lot of cranking on the engine... (and only then); that would mean that fuel is getting stuck in the carb instead of passing through and the cranking was creating pressure enough to force gas out of the gasket if that valve was stuck closed, right?
I'll order a new gasket for the center of the carb so I can take it apart and make sure its working properly.

I ordered a replacement coil for testing, which was inexpensive, and I wanted peace of mind on the spark issue... here's why: after the initial overheat, I had to take the boat to the mechanic to replace the impeller in the stern drive because the housing was corroded and I couldn't separate the upper and lower on my own. After they did that work, they called me and said that they were having trouble getting the engine started, and asked if I'd done any other work that might have affected starting. (I hadn't) They said they only had to prime the carb to get it started at that point. That was prior to removing the carb at all, which, coupled with feeling like the spark was looking pretty weak on testing, makes me feel like replacing the coil can't hurt either way.

For the choke, I've since learned that the coil spring in the electric choke thermostat housing is responsible for the position of the choke plate. I have the Idle adjustment screw on the lowest step of the cam. (And thank you for verifying that I've got that right, ...been wondering)

Will report back after replacing the coil and clenaing the carb's interior-

Finally, just in case... a previous post said to make sure that i didn't "Remove the safety lanyard from the ignition switch." Best I can tell, my boat doesn't have a safety lanyard at the ignition switch, and I figure this would be a pretty obvious item, right? Like a big tag sticking out of the dash? It'd be awful if I was getting bit this long by something like that...

 

[telstar1]

Re: Engine wont start after removing carb

I am unfamiliar with petronix ignition, so will ask this question. Are there two wires going to pos term on coil? If so,(googled Petronix it says yes) this means it is set up for 12 volts when starter is activated, 6+volts(thru resistor) when running. Sometimes the 12 volt wire is not delivering. Try rigging a temp wire from + batt term to + coil term and observe spark.It should be blue and jump a half inch or so. Dont leave this wire hooked up, and only do this if you have found it to be a 2 voltage syst(all points systems are, not absolutely sure abt petronix)If this procedure does not improve spark look elsewhere for weak spark cause.
Second item, fuel. If gas is leaking out of carb gasket, float is stuck or float level is too high. Fix this.Verify it is fixed by priming carb with fuel pump, look for stray fuel.
Third item , the engine is pretty well sure to be flooded. Both from all your trying and the high carb fuel level. If level is high enough to leak out of carb gasket its also leaking into engine.A seriously flooded engine wont start.Remove spark plugs and blow fuel out of cylinders. Be extremely careful doing this you will have gas all over h---and fire is a real possibility..Make sure ignition system is deactivated so you dont have sparks jumping around,shut off fuel supply to engine,have fire extinguishers handy etc etc.now roll engine over on starter.(With plugs out)Gas will gush out most likely.Once youve gotten most of the gas out of cyls doing this, get a compressed air hose and blow air into cyls rotate engine at same tme if poss.Get things good and dry Put plugs back in, engine will start. hopefully.

 

[shoestring]

Re: Engine wont start after removing carb

I am unfamiliar with petronix ignition, so will ask this question. Are there two wires going to pos term on coil? If so,(googled Petronix it says yes) this means it is set up for 12 volts when starter is activated, 6+volts(thru resistor) when running. Sometimes the 12 volt wire is not delivering. Try rigging a temp wire from + batt term to + coil term and observe spark.It should be blue and jump a half inch or so. Dont leave this wire hooked up, and only do this if you have found it to be a 2 voltage syst(all points systems are, not absolutely sure abt petronix)If this procedure does not improve spark look elsewhere for weak spark cause.
Second item, fuel. If gas is leaking out of carb gasket, float is stuck or float level is too high. Fix this.Verify it is fixed by priming carb with fuel pump, look for stray fuel.
Third item , the engine is pretty well sure to be flooded. Both from all your trying and the high carb fuel level. If level is high enough to leak out of carb gasket its also leaking into engine.A seriously flooded engine wont start.Remove spark plugs and blow fuel out of cylinders. Be extremely careful doing this you will have gas all over h---and fire is a real possibility..Make sure ignition system is deactivated so you dont have sparks jumping around,shut off fuel supply to engine,have fire extinguishers handy etc etc.now roll engine over on starter.(With plugs out)Gas will gush out most likely.Once youve gotten most of the gas out of cyls doing this, get a compressed air hose and blow air into cyls rotate engine at same tme if poss.Get things good and dry Put plugs back in, engine will start. hopefully.

X2 on the fire extinguishers!!! I mean 2 fire extinguishers! alot of pumping, cranking, starting fluid, pull plugs and crank some more going on, could be alot of fuel around. I'm sure you know to NEVER look down the throat of a carb with the engine running or cranking, at least not if you value your eyebrows. check your oil to make sure it's not getting full of gas. won't cause a starting problem but could cause damage once you get it running, being that it is not really oil anymore.

 

[JeremyL]

Re: Engine wont start after removing carb

Thanks!! I plan on clearing out the cylinders this afternoon. I'm going to "sponge" the spark plug holes with towels, and I'm going to tarp over the coil and distributor as well, just to be safe. I'll Disconnect the fuel at the fuel pump intake, and I'll have fire extinguishers on hand. : )

I got the new coil in the mail, and have a carb rebuild kit on its way (just in case). I'm feeling like the float valve Must be the culprit, along with a flooded engine. I"ll clear the cyls and install the new coil, then open up the carb and check the float valve (and general condition of the interior of the carb).

Will report back!

 

[hoot]

Re: Engine wont start after removing carb

some thoughts, is the carb fuel filter in the correct direction for fuel to flow? perhaps a wire was connected back wrong and you are not getting enough voltage to start. go to the pertronix site again and read over their trouble shooting tips. follow the wires to locate their terminals and where they are. your safety switch isn't always obvious if you have one (i think they are required now). how old is your gas? you may have fried your coil and pertronix system too when leaving the key on. try it with points and condensor, remember to put the rotor button back on. is your coil an external resistor or internal resistor type? if internal and using a wire or ballast resistor, your voltage will be reduced for spark. and are you using outdrive muffs to supply water to the foot? you will need these if it starts. a volt meter and volts at the + terminal of the coil would be nice to know when trying to crank the engine. if the previously owner used a pertronix coil, it is internally resisted, and the boat ballast resistor isn't used. an external resistor is required if using an external resistance coil.

 

[JeremyL]

Re: Engine wont start after removing carb

Ok- I opened up the carb to find a decent amount of buildup that looked like mineral deposits. I rebuilt the carb with a kit and its now very clean internally. The accelerator pump is part of the kit, and I can verify that it squirts two jets of fuel when the throttle is pumped. Fuel filled the carb quickly when reattached, but after a bit of cranking it started leaking fuel again, and I more accurately identified it coming from the throttle body assembly, instead of the gasket as previously stated.

I replaced the ignition coil, and when I did that, I made certain the cylinders were clear by pulling the spark plugs and cranking the engine. Not a lot of fuel came out... I blew compressed air into the cylinders to make sure, and again, a small amount of fuel came out.

Today after reinstalling the carb, it didn't start. So I retested the spark by plugging a spare plug into the end of each lead. Plug 1 sparked once in 5 seconds. Plug 2 sparked as it should: a bit faster than once per second. Plug 3 sparked almost constantly, and stronger than the rest. Plug 4 had no spark at all.

I'm off to test voltages at the ignition coil, and to run through the pertronix troubleshooting steps. The coil is internally resisted. I've got the sterndrive in a tub of water just in case the thing starts-

 

[JeremyL]

Re: Engine wont start after removing carb

The carb isn't leaking anymore. Nothing wrong with it that would stop the engine from starting (that I can tell).

I installed a test spark plug to each lead coming off of the distributer again (one at at time)- This time there was weaker sparks all around, and #3 got lame like the rest. I talked to a marine parts store guy, who told me that the pertronix ignitor is propbably working if I see any spark at all, and if it were bad, I'd have no spark at all. (dont know if that's accurate or not, the guy wasn't "sure")

That led me to sand off the minimal carbon build up that was present on the distributer cap points... but I am once again a loss for even a potential cause of failure at this point. I am not able to properly test the voltages for lack of an assitant today. This behavior reminds me of robodoc's previous post, so I might replace the distributor cap for testing.

I performed the standard 'rotor' test, and the high tension lead did not spark over to the rotor, which indicates proper grounding.

Seems if I have a spark at all, the difference in behavior of attached spark plugs could only be the cap and rotor, right?

 

[telstar1]

Re: Engine wont start after removing carb

Do you have a great spark coming from the coil?and does the coil wire go to the MIDDLE terminal on the distributer cap?What about the hi voltage wires are they good? Try spraying with wd 40 and setting them someplace warm overnight,along with dist cap. See if that makes a diff. You need a healthy spark. Did you try the 12 volt jumper wire thing?

 

[JeremyL]

Re: Engine wont start after removing carb

There is only one red wire coming from the Pertronix ignitor to the + term of the ignition coil. (and a single black wire from the ignitor to the neg term). I didn't do the wire test because I understood you to say "only do this if you have found it to be a 2 voltage sys" which I am thinking I don't. (?) I have a helper coming so I can test actual voltages at the coil points and see if I can determine anything-

 

[Gary H NC]

Re: Engine wont start after removing carb

I did not read the last 30 posts but have you tried a direct 12 volt and ground from the battery to the coil?
Also i have seen dist. caps that look fine on the inside but were no good.

 

[JeremyL]

Re: Engine wont start after removing carb

I tested voltage at the coil: + terminal sits at 5.5 with the key in the On position, and jumps up to 9.6 (peaking at 10) when cranking. The - term sits at 1.0 with the key at On, and 6.1 when cranking. I have a running car jumpered to the boat battery to ensure proper input voltage. I read 13vdc at the + term of the battery during this test. Should I have 13 at the + term of the ignition coil while cranking?

 

[JeremyL]

Re: Engine wont start after removing carb

I did not read the last 30 posts but have you tried a direct 12 volt and ground from the battery to the coil?

Going to do this now and will report back.

 

[JeremyL]

Re: Engine wont start after removing carb

I did not read the last 30 posts but have you tried a direct 12 volt and ground from the battery to the coil?

Yes- I connected cables from the + and - terms of the battery to the + and - terms of the coil. No change in behavior. I'll replace the distributor cap tomorrow and test.

I learned today is that the distributor rotor spins slower on cranking than I'd thought... I was looking for a spark to come at a shorter interval than what the actual rotor speed should deliver. That doesn't explain why I can go a full 5 seconds of cranking and see no spark, but it helps set my expectations.

 

[krisnowicki]

Re: Engine wont start after removing carb

dont connect the - of the coil to the battery just the + to the + try this again I am with him I bet it works

 

[telstar1]

Re: Engine wont start after removing carb

If youve got both + and - coil terms hooked to battery you are overloading coil with constant current for one thing, which will quickly overheat it or worse. As well, Id be surprised you got any spark with that hookup. Try just the pos jumper, it is now possible youve fried coil not sure,as i said petronix not my specialty but I do know for sure about the neg wire NO. ... .

 

[wire knot]

Re: Engine wont start after removing carb

She sure is giving you a fit .
Have you verified distributor is firing #1 cyl. at top dead center?
Finding top dead center:
http://forums.iboats.com/showthread.php?t=427081
When you are sure of TDC, look at the rotor to make sure its pointing at the #1 pin on the Dist.

Check to make sure the plug wires aren't crossed, (hooked up correctly).

Sounds like you got fuel.
You said compression was good, soooo,
Make sure you have spark, AT THE RIGHT TIME.

Somewhere on this site there is a list to troubleshoot the whole
starting system, I couldn't find it. You need to go through it SYSTEMATICALLY.

I'm sure these things I've mentioned you have covered.
Just trying to help.

WK

 

[fat fanny]

Re: Engine wont start after removing carb

wire knot you beat me to it but it is long passed time to start with the fundamentals of using the manuals teating proceedures one component @ a time with the proper OEM manual this can all be done with a multi meter by yourself using these proceedures takes allot of guess work out of the mix and proves out every component. Problems like these are best done by the book it will eliminate allot of frustration and time! Good luck.

 

[JeremyL]

Re: Engine wont start after removing carb

That's one of the things that's making this so difficult for me to figure out: The steps to troubleshoot the ignition system in the service manual can't be done because of the pertronix ignitor... I've tested the primary circuit per the book: pass. To test the secondary circuit, I am supposed to expose the points and take the high tension lead to 1/4" away and use a screwdriver to close contact and verify spark.... i.e., I have no points to test, and several troubleshooting steps involve those points. Its been a "grrrr point" for me.

A fit to be sure... I will redo the cable from the + battery to the + coil test. I'll to the Top Dead Center test leater today and report back-

Thanks to all!

 

[Willyclay]

Re: Engine wont start after removing carb

The steps to troubleshoot the ignition system in the service manual can't be done because of the pertronix ignitor.

My experience with Pertronix Ignitor units is they are reliable and dependable. This experience was many years at work with a fleet of vehicles so-equipped and most recently with my neighbor's 1977 MGB. They either work or don't! The Technical Support folks at Pertronix responded promptly and professionally to my email inquiries. Why not give them a shot at your questions? Good luck!

Try here: http://www.pertronix.com/support/default.aspx