470 mercruiser no start

[e5earley]

First a little history. Last September I got the 470 running after doing water pump sleeve and complete carb rebuild. Engine was easy starting, idled good. Started outdrive rebuild and completed last week. Installed new battery this week.

Now engine will not start. Compression test on cylinders is 120,120,121 120. Replaced coil, points, condenser, cap, and rotor. Tried starting on ether to rule out carb issues. Installed spark tester on all wires and shows spark. Timing has not been touched. I lined up timing mark and rotor is pointing toward #1 plug. Coil voltage is 12volts on + side with switch in run position. Not sure why the resistance wire is not dropping voltage. But that wouldn't prevent it from starting would it.

 

[Bt Doctur]

rotor does not "point" to #1 cylinder or sparkplug. with #1 at TDC compression the rotor points to #1 in the dist cap. firing order is 1,3,4,2

 

[e5earley]

That's what I meant. #1 in dist cap.

 

[Bt Doctur]

have you tried pouring some fuel down the carb

 

[e5earley]

Tried starting fluid. Haven't poured fuel in there yet.

 

[Bt Doctur]

plain old gasoline is a lot better that ether

 

[Mercruiser420]

Old gas, dwell/gap off, timing off (need a timing light). How do the plugs look? The voltage will drop when the points are closed and show 12v when theyre open. Firing order 1-3-4-2. Distributor spins clockwise. If its the first start of the season, I'd be leaning towards old gas, even though you sprayed ether the old gas could still be dripping down wetting/fouling the plugs. But do check the other stuff of course. Good luck

 

[e5earley]

Poured gas down carb. Engine hits a few times and tries to start but won't ever completely fire off. Going to check point gap again. And verify spark at each plug.

 

[e5earley]

Went ahead and pulled carb and think I may see the problem. Bunch of bad fuel pooled in the intake. Cleaned it out and disassembled the carb and cleaned it. In the process of pumping all the fuel out of the tank. Ethanol is the devil.

 

[JerryIrons]

I just buy 100% gasoline for all my small engines and boat and stabilize it year round then I never have to worry about it.

 

[e5earley]

Engine is running. Created a lot of additional work chasing ignition gremlins that didn't exist. But now I have all new ignition components, spares in the boat, a clean fuel tank, and a grin on my face.

Thanks for the help everyone.

 

[e5earley]

Spoke too soon. Got the boat to the lake and still not running right. Would not start at all. Corrected a choke lever issue and it will now fire off, but not run longer than a few seconds. Pulled plugs and they are black and sooty.

 

[Mercruiser420]

Carburetor flooding?

 

[e5earley]

Not flooding. Only way to get it to crank is by pumping the throttle to prime carb. Not sure if doing this too much fouled the plugs. Going to check today to see if parts counter cross referenced the correct plug. May not be hot enough. Or my idle circuit in the carb may have issues. Strange it ran fine at the house but the closer it gets to water the worse it gets.

 

[Bt Doctur]

It could be allergic to water, might have to pull it around on the trailer for a few miles.
2 aspirins in the gas tank might help

 

[Mercruiser420]

When you say at the water does that mean underload (in gear)only or in idle too?
Idle speed set correctly?
Air/fuel set correctly?
Do you have any exhaust problems/water leakage?

 

[e5earley]

Ran fine on muffs at the house. Idle at about 750. No exhaust problems or water leakage. Was able to kill engine and restart several times. Pulled it to lake that evening. Didn't try to launch until next afternoon. Wouldn't start when I backed down ramp. Took it back to camp and noticed loose battery cable. Corrected that and corrected a choke lever problem. Next morning tried to start several times and finally got it to run and idle a bit. Took it to boat ramp and that's when it started cranking then only running a few seconds. Took it back to house and put it on muffs where it exhibited the same problems. That's when I pulled the plugs and noticed carbon fouling. I've got a local guy that's specialized in quadrajet carbs for 40 years. I'm going to drop the carb off and have him go through it. That way I can rule that out. While it's there I'll check fuel pressure and point gap again. I'll need to find a dwell meter and timing light while he's getting the carb done. I was trying to get this going for spring break with the kids and was pretty rushed. I'll probably find something simple that will make me feel stupid.

 

[Mercruiser420]

When you check your timing hook up the light to wire #1 and wire #4 and check if they're firing at the same time. If not your distributor is worn unevenly and you'll have to either replace it or switch to electronic ignition which is the way to go IMO. Good luck

 

[JerryIrons]

I would bring a small bottle of gas and keep it in the boat to help you troubleshoot this at the dock. Kind of sounds like you just need to go over everything methodically, you already found a loose battery cable and choke lever.

Before you start take off the spark arrester and see if fuel gets squirted in the throat when you pump the throttle. Check that fuel filter out as well.