Engine almost starts then dies...and ideas?

PDACPA · **Posted:** Mon May 21, 2012 9:36 pm

Here is my short story.

Boat running great, stalls out. Cranks will not start. Short tow to Marina thinking low on gas or water in tank. Takes 22 gallons of fuel in a 32 gallon tank. Fires right up. Drive back to ramp (about 30 minute run, no wake and at speed).

Week later, put in a new fuel filter ( old one had no water in it) and treat the tank with Sentry fuel treatment in case of water in the fuel tank.

http://www.sentrytreatments.com/

Cranks, almost catches, won't stay running. See fuel shooting in carb. Pull fuel filter, top it off with fuel, but was full from when I put it on and re-coated the seal. Same problem, won't start. Check forums, they suggest anti-syphon. See my thread on it, but finally installed new anti-syphon and pick up. Engine does the same thing.

Change the plugs (old ones were pretty bad. Change the distributor cap (some corrosion), change the rotor too. Replaced one spark plug wire as it broke during plug change. Engine does the exact same thing.

Install a new relay at the fuel pump (it had some corrosion). Try again, engine does the same thing.

I have to been able to get a new fuel pump, but searching for one tomorrow. Is there anything I overlooked? I see fuel shooting into carb when I pump th throttle and it almost starts, but will it stay running.

Here is a link to a video of what it does. Any advice is or ideas is appreciated. Admiral is praying runs for memorial day!

Sanmiam · **Joined:** Sat Mar 24, 2012 9:05 pm **Posts:** 84

Fuel-Air-Spark-Timing. That is all a carbed engine needs to run.

You have isolated out that the engine is getting fuel so lets move on.

You replaced the plugs - can you confirm that you are getting spark to each cylinder? Get an old plug and test each plug wire (pull from plug on engine, stick loose plug into connector, crank) to confirm it is getting spark.

If no spark to the plugs (or it is only on a couple), then you need to move onto timing. Is your coil getting power? Is there Water or moisture in the distributor? I have seen more than a few engines that sounded similar from swamping and after a copious amount of WD-40 into the distributor it fired up. (WD stands for Water Displacement BTW). If you pull the cap to spray WD40 make sure you mark its position so you do not mess with the timing when re-installing (install in same orientation - not sure if it applies to this distributor setup, but some are not symmetrical on cars). In retrospect - I would try this first.

If this still does not work you can always go for a new cap to see if it does anything different. You should be able to pick one up from your local big box auto store. (Again, make sure the old/new are marked so you don't play with timing)

Past that the only other two options are either timing itself (in which case I would suggest googling a how to), or some sort of physical damage to the engine (can be diagnosed via compression test).

From the sounds of it I would tend to lean on either power to the coil or water in the distributor.

If anyone else has a suggestion fire away!

PDACPA · **Posted:** Tue May 22, 2012 6:09 am

I replaced the distributor cap and rotor. Saw no signs of water any where there. Used no WD-40 there at all. I did not do your test for spark ( will try today), but a friend helping says we had a spark.

I am thinking the fuel pump is not spraying gas in the carb and the only gas getting in there is when I choke it and pump the throttle trying to get it to catch.

Sanmiam · **Joined:** Sat Mar 24, 2012 9:05 pm **Posts:** 84

Then try having one person start it while the other sprays carb cleaner down the intake. If it runs off the carb cleaner you know it is fuel.

If you can limit down to fuel pull the feed line from the carb (or somewhere before it) and make sure you are getting a good supply. If not, it is the pump, if so it is most likely the carb is not jetting properly.

PDACPA · **Posted:** Tue May 22, 2012 6:45 am

Tried that with starting fluid. Would not catch.

Sanmiam · **Joined:** Sat Mar 24, 2012 9:05 pm **Posts:** 84

I'm sure someone else will say otherwise, but I have never seen a fuel issue where the engine would not run off starting fluid.

Bliss36 · **Posted:** Tue May 22, 2012 6:52 am

How does your spark look? Bright blue? Also if you or anyone else has a wiring schematic for this engine could you please post it?

Sanmiam · **Joined:** Sat Mar 24, 2012 9:05 pm **Posts:** 84

http://www.4shared.com/dir/14518366/adf ... aring.html

Try downloading it from here.

ric · **Posted:** Tue May 22, 2012 7:17 am

For the age of the boat, that stuff sure looks crusty but anyways..

I have an idea. Do me a favor and put your hand over the carb. Block off the airflow or most of it. See if it runs.

PDACPA · **Posted:** Tue May 22, 2012 7:26 am

Need to get someone to help, home alone now Ric, but will try the hand over the carb.

Does anyone think the fuel pump is the culprit? Trying to find one to eliminate that from the equation.

It ran fine after that stall out on the water last week after getting more fuel. And had run fine the 3 or 4 weekends prior.

298VISTA2000 · **Posted:** Tue May 22, 2012 7:35 am

Have you taken the carb off and inspected it for ethanol damage? My generator was having trouble like this so my tech replaced everything (including fuel pump) and it ended up being the carb that was fouled. He took it home and cleaned it up and said it had something to do with the pin (real tech savy here). Good luck and hope you make Memorial Day.

PDACPA · **Posted:** Tue May 22, 2012 7:50 am

I have not done much more than verify fuel shooting in the carb.

I hate to take it to my mechanic this late, but I am running out of time to have it ready for Friday.

ric · **Posted:** Tue May 22, 2012 8:01 am

Ethanol does not physically damage anything. It's the water it soaks up from sitting that causes engines to run bad. Gasoline on the other hand.... that's another story.

Here's my friend's pressure washer I fixed the other day. This is what happens to gasoline when it sits inside your carb for a few months. It turns to varnish when it evaporates and plugs all the little holes. Gross. Ethanol based fuels loosen all that crap causing it to get sucked in the carb plugging it worse (the alcohol in the gas is an awesome cleaner!!) That's why when someone has an old boat and runs E10 for the first time their fuel system basically gets plugged like a cork from all the gook that was set free.

You on the other hand, I think you have a vacuum leak. That's why I want you to put hand over carb to limit the air going in (to compensate for the leak)

Sanmiam · **Joined:** Sat Mar 24, 2012 9:05 pm **Posts:** 84

Not sure on this particular carb what the range of motion should be, but after watching the video again - is your choke valve sticking by chance (that flap you moved over the carb)? It should be silk smooth in its operation. Not sure if it would cause your problem, but something to be aware of.

PDACPA · **Posted:** Tue May 22, 2012 8:23 am

Sanmiam- it is a bit corroded. It moves with my fingers, but I would not say "silky" smooth. I will try and clean it up.

www.iFourWinns.com

Engine almost starts then dies...and ideas?

Who is online