Re: Hard Start after Warm
I've been searching the net to find a problem similar to the one i'm currently experiencing, and this thread looks about the closest! I can see a lot of helpful comments here, but CP611 never actually got his carb fixed, he replaced it, and well, i'm hoping to fix mine without replacing it..! Can anyone give any tips?<br /><br />My problem relates to an old Mercruiser GM 3.0L 181 C.I.D. engine, with a Mercarb 2 Barrel Carburetor. I was suffering from real bogging problems accelerating from idle, so I bought a service kit, and attempted a do-it-yourself carb service. The bogging problem was easy to fix - the Accelerator Pump Shaft & Lever assembly had loosened off the Accelerator pump, causing a large amount of slack. This is fixed, and my 'hole shot' is now beautifully smooth, with no bogging & no hesitation. The engine is running smoothly, ticking over evenly, with no evidence that i've screwed up anything ;-)<br /><br />...However, I seem to have created a new problem! As people have described above, the problem occurs after stopping the engine when warm, then attempting to restart after waiting about 5-10 minutes (restarting immediately after stopping is fine).<br />When this problem occurs, the engine is comlpetely flooded, so much so that rather than coughing & spluttering (how I remember flooded engines sounding) it just turns over fast & smooth with no hint of any combustion at all. I don't know exaclty how long it takes to clear, but it's more than an hour. Coming back to the boat the next morning, it starts ' on the key' as if there were no problems at all..<br /><br />When I look down the barrels after turning off the engine from warm, I can see a steady leak of fuel dripping (at a rate of about one drip per second) from each branch of the venturi cluster at the end of the 'V' that is directly over each barrel of the carb. I can also see big puddles forming on the back of the throttle valves, and a fair amount of fuel around the flat surfaces of the body at the tops of the barrels. I can't see
exactly where the fuel is coming from, but i'm fairly sure it's coming through the venturi cluster brass tubes, rather than leaking from the venturi cluster gasket.<br /><br />I've had this thing apart again a couple of times, but everything seems just fine, and i'm out of ideas! It would be great if I could get some pointers...<br /><br />I've got some specific questions also, based on other peoples advice in this thread:<br /><br />Q1: Where are the well plugs? Can I spot if they are leaking? <br /><br />Q2: I don't know enough about the carb to understand exactly how the fuel gets from the float bowl through to the venturi. I'm going to check (again) as follows:<br />1) Main metering Jets & Gaskets<br />2) Power valve assembly and gaskets<br />3) Venturi cluster main gasket & center screw fiber washer<br />But can anyone tell me if i've missed anywhere that might be repsponsible for fuel leaking through into the venturi cluster?<br /><br />Any Ideas or pointers VERY greatfully received! Oh yeah, and this is my first post here, so hi everyone!! I promise to come back and let you know what the final solution was, and i'm hoping it won't be "Buy a new carb!"<br /><br />BTW while I was searching, I found a full MerCarb service manual PDF online at
http://www.boatfix.com/merc/Servmanl/13/13B5R2.PDF <br />responses quoting page numbers and diagram references would be even more helpful (if i'm not being TOO cheeky!)
