Strange problem (carb?)

🇮🇹💦 Of the Loin /

I'm noticing on my garelli that when I pull the throttle out to full (and it starts at about halfway) it starts sucking in alot of air and bogs down. Its very noticible if you put your hand over the carb( brand new) at full throttle. what makes it do this?

Re: Strange problem (carb?)

Unfortunately your discription of what is wrong is not good enough for any mechanic to decifer. Does the motor start easy, does it idle ok. will it accelerate to 1/4 or 1/2 or 3/4 throttle before it dies. What was apparently wrong with your first carb? why did you change it, Did you actually buy a new carb, or just a different used one. All carbs suck air and the ventury inside causes the air to suck fuel up out of the carb into the air stream to mix properly ( about 14 pounds of air to one pound of fuel is the proper mix) If the choke is on you get too much fuel (gas) and the mixture won't burn, it floods, but if the intake has any crackes or air leak then it will get too much air, not enough gas and the motor will be very hard to start but scream fast if it does start and you can't adjust the idle.

Re: Strange problem (carb?)

🇮🇹💦 Of the Loin /

sorry. The motor starts fine, it idles for a while (several minutes) and then dies, and when I accelerate it never dies, it just makes a deeper noise than usual and begins to bog down as well as create a vast increase in suction through the carb air filter (putting your hand near it will let you feel the suction)

Re: Strange problem (carb?)

Jason Luther /

the suction is normal, thats how the air gets in there. you said the carb noise is louder and deeper? has any part of your airbox fallen off? do you have the big gold, loaf of bread looking thing that fits onto the carb, or just the screen that fits on the carb? the loaf of bread from time to time may wiggle loose, and it has those black plugs in there. the bogging is just as you said, not enough fuel. so if your airbox is in order then your main jet in your carb is probably dirty.

Re: Strange problem (carb?)

🇮🇹💦 Of the Loin /

Im aware of the natural suction, but this increases it dramatically when i increase the throttle above halfway. I dont have an air box, I just have the air filter that goes over the carb (its a Dellorto SHA 14.12)

It sounds to me like too much air and not enough fuel but I just got into fixing them so I dont know

Re: Strange problem (carb?)

George Smith /

the opening of the throttle does 1 thing....allows more air in....thus sucking more fuel and air mixture into the motor....thus more rpm.....so if your jet is good you wont get a bog down sound you will just get more rpm :) clean ur jet :) or upjet :)

Re: Strange problem (carb?)

🇮🇹💦 Of the Loin /

Its a brand new 53 Jet and I checked it out and it looks clean

Re: Strange problem (carb?)

George Smith /

upjet then

Re: Strange problem (carb?)

Jason Luther /

if your carb is clean check for another air leak somewhere. spray some carb cleaner around all the connecting points (base gaskey, intake gasket, etc) and see if there is a change in rpms, if so you have found your leak.

Re: Strange problem (carb?)

🇮🇹💦 Of the Loin /

well after taking the engine apart to look at it, it seems I have no main gasket, there is what looks to be some corrosion and rust in the intake valve, and some good carbon deposits on the exhaust valves on the side of the block. Im sprayed it all down with some carb cleaner, and later Im gonna take a file to the intake valve and get some corrosion off.

Im also gonna try and get ahold of a main gasket now too.

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