Carburettor repair

[treemasher]

Hi there just bought a repair kit for walbro wt500 carb on a husqvarna 225h60 hedgecutter has anyone done one of these if so are they relatively easy and do you have any tips as it's my first cheers

[adw]

When you say repair kit, is it just diaphrams and gaskets? start with the pump side ( alloy cover held with a single screw ) remove the gasket, and pump diaphram, replace the the fuel screen if in the kit, you should not really just clean this as the mesh is very fine, clean fuel channels with carb cleaner, fit the new pump diaphram against the carb body, followed by the gasket and cover. Remove the four screws holding the metering side cover, under here you will find the metering diaphram and its gasket in that order, if you have a new fuel needle ,remove the screw securing the metering lever, remove the metering pin, lever and needle, be careful not to lose the spring, now remove the H and L mixture screws, clean through all the fuel channels with carb cleaner, if you have new core plugs in the kit be very carefull removing the old plugs as it is easy to damage the carb body, re fit the metering lever and needle, use new if suppled in the kit, the metering lever should be level with the the sides of the carb body, pry up if too low, bend down if too high, fit the gasket and then the metering diaphram and cover, re fit the H and L screws, gently in onto there seats and back off one turn on each, fine tuning will ned to be done during running the engine. The are fuel screws so unscrewing them will ritchen the mixture, if the machine hesitates on pick up ritchen the L screw a little, max rpm should be set with a taco, if you do not have one set the max rpm so the engine is four stroking.

[Dan Forsh]

Hi,

 

Just to be clear; an overhaul kits is usually just the diaphragms and gaskets, a repair kit is these plus needle, metering lever, spring, gauze and welch plugs. It's important to understand that a lot of these kits are universal in terms of they are intended to cover a few different carb models from that particular manufacturer's range so may have multiple gaskets and multiple diaphragms included. Determine which ones you need based on what you are taking off the carb.

 

If you have all this in the repair kit then replace with new all those parts supplied apart from the welch plugs unless you know what you are doing with these. Generally you shouldn't need to touch these unless the carb is really bunged up due to age, abuse. The other items plus a can of carb cleaner and/or an ultrasonic bath will be enough in most cases.

 

Otherwise everything adw has said will guide you. If you don't understand what he means by four stroking, it's a burbling sound (too rich) just YouTube tuning a 2 stroke engine for more detailed info.

[GardenKit]

Excellent replies from both ADW and Dan.

 

But, I question the detail on setting the metering lever. Various carbs have different settings and many, such as HDA etc are indeed level. But all the WT carbs I have ever encountered actually have the lever set around 2mm below the flat body surface.

[peatff]

Watch out for the spring when you take the lever out. They are sneaky little beggars.

[spudulike]

Have your phone ready to snap a pic each time something comes off as it is sometimes easy to get the order of the gaskets and diaphragms the wrong way round.

 

This is far less likely if you have done many before but I have encountered it on a few machines in the past.

 

I would avoid changing welch plugs (those small aluminium disk caps), they need sealing and compression to make them fit and even I only change them if a leak or a runnig issue demands it.

 

Make sure the spring under the metering arm is sited correctly and note what Gardenkit says about the metering arm height - take a look at the height of the original BEFORE it comes off and match it.

 

Lots of good advice - don't let it scare you and just take it step by step!

[treemasher]

Great thanks lads I'll keep you posted on how i get on cheers

[Sandworks]

Tbh you would do well to get an ultrasonic bath, as the crud that builds up will not be moved with carb cleaner alone, it may look clean but after years of doing services without ultrasonics the difference it makes in the carb is fantastic, I bought a 6 l one not to long ago and it is the mutts nuts,

One of the quads was running like crap, stripped carb down and gave it a good 2hrs in bath at 80 deg, runs very well now, will still be doing a full jet and needles replacement though,

If you are unsure of method,a quick search of you tube and you will find the right video for your carb type!