# Husqvarna Riding mower - carb problems



## rreemo (Jul 9, 2007)

Hello,
I have ~2005 Husqvarna riding mower with a Briggs & Stratton Vangaurd engine (model #385777), that has started running poorly. The first time this happened I was pretty sure that I had gotten some bad gas...it started missing a little, then progressed to backfiring, and finally noticed that the muffler was glowing orange. Simply draining the fuel tank and refilling with known good gas seemed to fix the issue. 

After a couple weeks, this issue happened again. This time, I crimped off the fuel line and let it run out of fuel, then replaced the filter, and it again seemed to run fine; however, after letting the mower sit for a few days, it happened again. It has now gotten to a point where it does it all the time....do see some dark smoke out of the exhaust as well. 

I've blown out the fuel lines, replaced the gas again, and have now removed the carb to check the needle/seat....I did notice a very small bit of trash in the bottom of the bowl, but not much at all....other than that everything looks normal to me. I was planning to blast it out with some carb cleaner, and then blow it out good with air, but after that I'm not sure what else to try (if this doesn't fix it).

Also wondering how low the float should be set?

Any other suggestions would be greatly appreciated!


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## AIMandroman (Jul 26, 2019)

*Following: Snapper ZTM with Vangaurd engine*

Following this post: I have the same issue with same engine.
I replaced fuel pump.
Cleaned/re-gapped sparkplugs
Checked/cleaned air filter
Checked compression on both cylinders (125psi and 126psi)
My machine has 654 hours on it, which is not enough to "break" this engine.
lithium138 @ yahoo . com


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## paulr44 (Oct 14, 2008)

Good info. by AIMandroman above.

Dark smoke, but glowing muffler? Kind of opposite symptoms. Blue or whitish smoke is oil, black is excessive fuel.

Glowing muffler indicates a lean mixture. Could be a vacuum leak. With the engine idling and the air filter cover off, spray carb. or brake cleaner
around the manifold gaskets by the cylinder heads. Air filter housings often take air in from behind/under and test spraying with the cover on could allow some of the spray to enter the intake and effect the test.

Could also be leaking head gaskets (as suggested above, take a compression test). They often used graphite back then, which degrades over time. You can look at the mating point of the cylinder heads to the block for indication of a leak...there will be black, oily residue emanating from the gasket area if so. Compression between cylinders should be no more than 10% difference.

Adjusting valve lash after this many years would probably help too. Spec. for both intake and exhaust is same: 0.004"-0.006", cold.
If for any reason you decide to clean the carb., you should know the main jets are different in size, and must be kept respective (left vs. right).


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