MS230C carburetor Puzzlement

beaverplt

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I have a Stihl MS230C in for repair of what should have been a simple job. It hadn't been run for two years. I disassembled the carb, cleaned it in our sonic cleaner, ordered and installed all new gaskets, and reassembled it. Now when I prime it to start, I get no gas flowing into the carb. I pulled the gas line and gas spewed all over me. Apparently, the primer worked in pulling gas up to the carb. It just stops there. I disassembled it again to check if I perhaps assembled it incorrectly. I did assemble it correctly. I checked for flow through the intake and it's clear. When I assembled and installed it again I have the same issue. Any ideas what could be constricting the flow after assembly? Thanks
 

Hammermechanicman

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Going to assume you assembled the fuel pump properly. Is the impulse line hooked up and is it in good shape. Non working impulse can cause metering diaphragm not to move so no fuel past needle. Do you get fuel i to the fuel pump section of the carb?
 

slomo

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Tank dirty?
Fuel filter in the tank clogged?
Fuel lines cracked or loose?
Diaphragm gaskets installed proper and new?

Fuel lines are probably cracked and dry from the two year vacation. I know I use Stabil fuel stabilizer and leave it full of gas and oil over the winter. Seems to save me from replacing lines and tanks. Drain them for the winter and I have to start replacing lines. Guess they dry our and crack with no fuel and oil in them in the cold garage. My trimmer fuel tank replacement was $86.00 alone.

slomo
 

slomo

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Is it a Harbor Freight sonic cleaner? Heard from someone here that had one, those are not that great in cleaning. He has another industrial type now $$$$. Your carb might still be plugged up??.

slomo
 

ILENGINE

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Put your ear close to the carb while priming and listen for a sucking air sound. I am betting that you have a check valve stuck open and it won't prime and may require complete carb replacement.
 

StarTech

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The HFT USC cleaner is only a 60W cleaner much like my first unit by Kendall and yes it will take several cycles in it to things clean. Even my 160 w USC takes a couple 30 minutes cycles sometimes but of course it got a 10 liter tank too.

Not familiar the MS230 carburetor; although, I have service a couple over the last 11 yrs. But said check valve(s) on the metering side can be stuck open and if so then it is a new carburetor time.
 

beaverplt

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Thanks for all the replies. Our sonic cleaner is a GT Sonic Professional cleaner. My first thought was operator error, so I double checked my assembly. The tank is clean, the gas replaced and the filter is good. One thing I didn't mention is the primer bulb never fills with fuel. Could the metering valve be stuck closed? Would that explain fuel being drawn up to but not into the carb?
 

Fish

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The primer bulb is actually a purge, it pulls fuel through the carb, and then sends it back to the tank. Check and see if you have the lines hooked up backwards.
 

Hammermechanicman

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The ms250 has a complicated primer system. It is not an air purge, it pushes fuel into the carb. The carb only has one fitting.Screenshot_20200809-114318_Chrome.jpg
 

beaverplt

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On this particular carb it's not possible to hook them up backwards. The supply line can't stretch to the purge line and vice versa. The diagram above isn't the same carb setup. I'll see if I can find the one I have.
 
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