How test crank case for air leaks

[CallumA]

How would I test a Husky 266 for air leaks in crankcase? I,ve cleaned the carb and set up the carb as per manual and set H screw so it four strokes at top end, it runs and cuts great until it gets hot then the idle speed increases and it revs high like its running lean!!

Your thoughts gents.

Edited June 20, 2014 by CallumA
Daft

[Stubby]

How would I test a Husky 266 for air leaks in crankcase? I,ve cleaned the carb and set up the carb as per manual and set H screw so it four strokes at top end, it runs and cuts great until it gets hot then the idle speed increases and it revs high like its running lean!!

Your thoughts gents.

 

You do have an air leek for sure . Spud will be along soon . He does this on a daily basis .

[wisecobandit]

Pressure test but unless you have a vac/pressure pump its not worth buying for one saw test and would make more sense to get someone who has one to do it for you.

Saying that theres only 2 likely/common suspects and that's either the intake manifold or crank seals.

You could try running the saw and spraying wd40 or carb cleaner around the intake manifold and see if the engine note/revs change. If that doesn't show any fault then I would say change the crank seals which are under a tenner before shelling out to many pennies for a pressure test.

 

Obviously theres an element of risk running any saw with an air leak.

[CallumA]

Where would I get a tester and how much would it be as i have 8, 2 stroke engines so the cost may be justified!

 

Callum

[mikerecike]

http://www.amazon.co.uk/gp/aw/d/B005O2LTFE?pc_redir=1402704846&robot_redir=1

This is what I have

 

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[spudulike]

You may have one of two things, something wrong with the fuel system causing the low speed fuel delivery to lean out a little or an air leak.

 

To do a pressure check correctly you need to plug all the ports and holes in the engine and then pressurise the crankcase and see if the pressure drops over time and do this also whilst rotating the crank. You also need to do the same with Vacuum in the crankcase as seals can seal 100% in one direction but leak in the other.

 

I use some home grown system based on a sealey brake bleader for vacuum and a gunson low gauge for pressure - it didn't cost much over £50 but is a little modified for the job.

 

Doing what I do, being able to perform these checks hs resolved many issues and also flagged up some impending air leaks before they have caused severe damage.

 

Any two stroke tech that doesn't understand why doing these checks is important, doesn't know his craft IMO!

 

So, your saw - you could plug all the holes, put some sort of adaptor on the spark plug hole and then inflate a baloon and use this to presurise the case and use soapy water around the crank seals and manifold to check for leaks - it may work for you.

 

If any seal will leak, 95% of the time it will be the clutch side one - you couldjust replace it and see if it resolves your issue:thumbup:

 

Buying the bit of kit is half the issue, plugging all the ports is the other, a friendly shop should do the job for an hours labour if you catch them at a good time but take it with the clutch, exhaist and carb off to save them the hassle but take the parts with you:thumbup:

 

Good luck