OMC Cobra 4.3L barely starting

[chr154k]

I just replaced my boats engine with an OMC Cobra 4.3 L. The engine turns over fine but dies as soon as it starts. I cant explain this as well as I would like to so I linked a video. The engine is getting fuel up to the carb, but from there I'm not sure. I have used carb cleaner and I also put a fuel primer in the line. This engine was sitting in someones shed for 6 months and I have not seen it run.

 

[Maclin]

Does it die as soon as it starts? Or is it more like it dies after you let the key spring back from cranking?

If it runs when cranking but dies as soon as key is released then I suspect the wiring to the ignition coil is not correct. There is a bypass circuit that gives the coil full 12v when cranking, then when key is released from cranking the ballast circuit to the coil is what supplies power thru ballast resistance, usually 9 volts or so.

All of that depends on what kind of ignition the replacement engine uses. Please describe what is on the new engine now (points, electronic, brand,etc)

Check voltage at the coil positive terminal (Meter black wire connected to Ground, red wire connected to coil positive) with the ignition switch in just On position, not cranking. Should be at least 8 volts and could be as much as 12. Zero volts means ballast circuit wiring is missing or ballast component(s) have failed.

 

[Lou C]

How about a clear vid of the carb, with the flame arrestor off..Is the Choke closing, are you advancing the throttle to give it fast idle?
For it to start the choke plate must close, you have to advance the throttle to give it fast idle and the choke unloader (vaccum break) has to pull the choke plate open a fraction of an inch.

 

[Maclin]

In regards to Lou's post, I ask also that you describe your starting procedure with regard to throttle lever movement, as in pumping once or twice in throttle-only mode, then leaving throttle slightly open when cranking...that type of thing.

 

[chr154k]

I will try these things and take better pictures tonight. As for the electrical problem, even if I hold the key in the start position it still just fires a few times and stops. I will check the coil voltage tonight though. I will also try starting with the throttle advanced a bit and pumping it.

 

[chr154k]

Here is a video where I tried the throttle around 50%. I also tried around 25% but no difference. Tomorrow I am going to remove the carb and clean it, although I really don't want to do that. I think it may not be getting any fuel, however the fuel line on the carb is corroded on. Im letting it sit with some liquid wrench on it overnight. I was really hoping to get this boat running by this weekend, but I remain stumped...

 

[Maclin]

So..looking down the throat (ENGINE OFF!) of the carb with flame arrestor off, when you move the throttle do you see or hear 2 good streams of fuel from the accelerator pump nozzles?

 

[chr154k]

Here are some pictures of the carb and what I believe to be the shift mechanism.

 

[chr154k]

Some pictures of the carb and engine. Anyone know where I can find the serial number?

 

[chr154k]

Sorry for the multiple posts, the pictures were really big.

 

[chr154k]

How about a clear vid of the carb, with the flame arrestor off..Is the Choke closing, are you advancing the throttle to give it fast idle?
For it to start the choke plate must close, you have to advance the throttle to give it fast idle and the choke unloader (vaccum break) has to pull the choke plate open a fraction of an inch.

I will make sure the choke plate is closing tomorrow, it may not be. I cannot see it very clearly when I start it as I do not have a remote start. If you see the video it does start though, it just stalls pretty much instantly.

 

[chr154k]

So..looking down the throat (ENGINE OFF!) of the carb with flame arrestor off, when you move the throttle do you see or hear 2 good streams of fuel from the accelerator pump nozzles?

I will check that tomorrow, but from what I saw I don't think so, I moved the throttle as I took those pictures of inside the carb.

 

[Lou C]

If you're not getting any spray of fuel from pumping the throttle, you need to check your fuel filters first, there is a small one in the inlet on many Rochester carbs. Most boats also have a big water separating fuel filter. The fuel pump could also be at fault. Have you checked for a spark at the spark plugs? The choke looks like its closing close to enough, depending on the temperature. On a real hot summer day it might not close all the way.
On OMC engines, the serial # was usually on a grey sticker on the thermostat housing.
Carb looks like a Holley 2bbl. Check for spark first, check accel pump, if you have spark, gas and a working choke it should start. BTW, you are missing your transom shift cable LOL....better take care of that.....

http://flyingfishcarburetors.com/Y42-2ST-2300-6-OMCVolvoPenta.htm

 

[chr154k]

Well guys I found the problem... The carb needs some serious cleaning and a rebuild. I do need help though, what should I buy? I looked up my engine model number (432aprrgd) and found a Sierra rebuild kit, is this the correct kit for my Holley?

List of parts for my engine:
http://www.*****************/parts/om...=Carburetor-2v

The Sierra kit that it says will fit:
http://www.*****************/newparts...num=SIE18-7238

Thanks so much for your help, the carb is sitting overnight in carb cleaner. While I wait on parts Im going to clean the connections in the distributor cap and flush the fuel system.

 

[chr154k]

Will it not let me link other sites? If not, all I did was google the engine model number and found the carb kit on marine engine's website

 

[chr154k]

Here are some pictures of the carb:

 

[Lou C]

You're not kidding it has to be cleaned lol...