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Discussion Starter · #1 ·
Hi,
I have been biting my head of getting my stubborn lawn mower (Husqvarna Rider R318) to work again. Hope you can help. It has a B&S Intek 17.5HP engine with less then 200 hours on it.
Problems began when I found the mower to be smoking (blue) making me feel sick after finishing the lawn. Stopped the mower, played with the throttle and when I gave it a blip to full throttle I could clearly see a lot of blue smoke coming out. Then suddenly the engine stalled and I couldn't get it running.

I took the valve cover off and there was A LOT of oil in there almost completely full. Not normal. Also the valves had to much play.
Took the head off and found the head gasket completely ruined (especially the side where valve guides are so this must be how the oil got in the valvecover). Changed the gasket and also cleaned the piston and cilinder/cilinder head (lot of carbon deposits).
Adjusted the valves and checked the clearances twice after a few rotations of the flywheel.
Cleaned the carb (not dirty).
Replaced the sparkplug.
Put it all back together, didn't fire up.

Took me long enough to find the solenoid / plunger in the carb fail not allowing any fuel in the engine. Cleaned that, fired right up but idle wasn't pretty like the timing was off. (put, put, put sound)

Replaced the ignition coil and set the armature air gap.

Idle is now beautiful like new and if I slowly move the control lever I can get it up to mid revs fine. If I push further (or blip from idle to full throttle) it will stumble and stall and can't recover and shut off with a big blow through the intake/airfilter.

When that happens I cannot get it to start again unless I come back the day after of if I empty the float bowl of the carb (Nikki). If I empty the fuelbowl it will start right up and same thing happens all over again.

It just won't go to full throttle. It looks like it is dumping a lot of fuel in the engine when I go to high throttle, overflowing it.
What could be the problem here?
 

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Discussion Starter · #2 ·
Oh and also, if I open the throttle control before I try to first start the engine it won't even fire up because it will be completely flooded with fuel coming out of the exhaust...
Carb problem?
 

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First thing that comes to my mind is the needle & seat. I remember you saying you cleaned the carb. You may want to throw a rebuild kit at it. If that's the carb with the white round disk and goofy looking round maze-like gasket, i have had problems keeping the gasket alignment during reassembly.
 

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Discussion Starter · #4 ·
Hi Freddie, after fiddling a bit more I purchased a new carb (was only around € 70), put it on and fired-up straight away. No issues anymore :)
Although the carb looked like new / clean on the inside there must have been something wrong with it.

And yes it is the Nikki carb with the maze like gasket, I have been very carefull with the gasket but problem is you cant look inside after you re-assembled it. Also the problem was there before I removed the carb so probably a needle problem caused it like you suggested. The new carb I received is the Ruixing apparently replaces this part number.
 

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Great news! thanks for the update - it really helps future viewers if they have similar problems.
It sounds like the carb was over fueling the engine causing the blue / oil smoke and related problems.
 

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Greetings -

I've got the very same issue- well I had the same issue- I have a Dixon with the B&S Intek 16.5HP - very low hours- it ran fine while new (Mother-in-Law's mower) but has mostly sat for the last 4 years - was running ok last year at Son-in-law's place. Then it sat more and finally came home with me- was difficult to start and had gas pouring out of carb. So I took the carb apart, found a torn float bowl gasket, no dirt - gasket is as described above - maze-like with a white insert in the upper part of the bowl containing needle and seat. Those are clean- I found a pack of 10 new gaskets for about $3- put it back together.

Here's the problem - it will idle all day long but when throttled up the throttle plate/governor will start to oscillate, oscillations will grow worse and worse till it dies. I'm going to take it back apart and double-check the needle/seat. And check that the float bowl is full-

Anyone have anything similar happen?

Best,
MikeB
 

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So!

Took the carb apart again - found a bit of dirt sitting on top of the needle housing which may have restricted the flow of fuel- That would do it if the engine is starved for fuel at high RPM-

ALSO! I put a new funny-looking bowl gasket in just a few hours ago - it went in with no issues, was the precisely correct size. But when I took it off, it had swolen and is now too big to properly seat in the recess between bowl body and white float insert... So I'm glad I bought 10 of these. Also what I notice is that there's a staked piece where the mixture screw should be and I'm seeing a squirt of fuel out of this whenever the thing oscillates and tries to die. So I've sealed it up, we'll see if that helps anything.

And I'm using straight gasoline, 100% -no ethanol (but who really knows, right-)...

Best,
MikeB
 

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Are you using any type of carb cleaner or brake cleaner? Some types will cause plastic and rubber to swell.
Didn't need to clean the carb - I replaced the gasket with a new one, engine isn't running right so I pulled the bowl off - new gasket was now expanded considerably when it came off the mating surface-
 

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Didn't need to clean the carb - I replaced the gasket with a new one, engine isn't running right so I pulled the bowl off - new gasket was now expanded considerably when it came off the mating surface-
Found a new carb online for $25 - pulled the trigger, not worth my time to continue to mess with this one-
 
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