How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Briggs-Fan Your Own Question
Briggs-Fan
Briggs-Fan, Small Engine Technician
Category: Small Engine
Satisfied Customers: 1264
Experience:  over 15 years experience in small engine repair, multiple certifications
75998144
Type Your Small Engine Question Here...
Briggs-Fan is online now
A new question is answered every 9 seconds

I have a Husqvarna YTH1542 riding mower with a Kawasaki FH430V

Customer Question

I have a Husqvarna YTH1542 riding mower with a Kawasaki FH430V engine. This morning I mowed for 45 minutes then the engine started to produce white smoke. Over the course of the next hour or so the engine would smoke, then stop while just mowing. There has never been a loss of power just on & off smoking. Can't see any oil leaks, no oil in the air filter. Thoughts or suggestions?
Submitted: 2 years ago.
Category: Small Engine
Expert:  Briggs-Fan replied 2 years ago.
Hi my name is ***** ***** welcome to just answer. Check you oil to see if it's thin or smells like gas , if so do not attempt to start or run it . I'll wait to hear back from you on what you find
Customer: replied 2 years ago.

It does smell some of gas. Can't really tell about being too thin. I run straight 40W oil.

Expert:  Briggs-Fan replied 2 years ago.
My concern is your carburetor may be allowing fuel to bypass the carburetor and get in the crankcase and mix with the oil. Is the smoke coming from the muffler ? Look at the muffler and is there anything dripping from it etc ?
Customer: replied 2 years ago.

There are no drips anywhere on the mower. The smoke was coming from the muffler area. I've had this problem for at least a couple of months.

Expert:  Briggs-Fan replied 2 years ago.
If the oil smells like gas it's a sign of the carb leaking , try changing the oil and run it , smell the oil before starting it and run it to see if it will smoke like this with the new oil
Customer: replied 2 years ago.

I changed the oil & filter about a month ago trying to stop the "smoking" problem. Just looked inside carb and there was an easily removable

black residue.

Expert:  Briggs-Fan replied 2 years ago.
When you say black residue does it look like oil , is the air filter have any oil stains etc on it ?
Customer: replied 2 years ago.

Inside the air filter enclosure there is a SMALL buildup of what looks like oil in fine dirt. Inside the carb the black residue could be from oil -- it was easily removed with a q-tip.

Expert:  Briggs-Fan replied 2 years ago.
That's a sign of blow by , it's when oil gets past the rings and into the air filter housing etc. From what your describing it sounds like a head gasket issue. The 40 weight oil isn't good for the engine. I would use 30 weight oil and check the head gasket
Customer: replied 2 years ago.

How do I check the head gasket? I'm using 40W oil because the Kawasaki manual recommended it for high temperatures like we experience in Houston.

Expert:  Briggs-Fan replied 2 years ago.
You can pressurize the cylinder and check for leaks. Also check this out , the symptoms were the same as yours
http://www.doityourself.com/forum/outdoor-gasoline-electric-powered-equipment-small-engines/318719-oil-carb-exhast-blowing-out-white-smoke.html#b
A bad head gasket would allow oil to get in the valves which would put on in the intake and exhaust valves
Customer: replied 2 years ago.

Does that account for gas in the oil?

Expert:  Briggs-Fan replied 2 years ago.
If your sure the oil has a gas smell to it that is the carburetor. The problem is you have symptoms for a few different things. Gas in the oil will make it smoke like you are describing and the oil will smell like gas etc. Is the tractor empty on has when you go to use it ?
Customer: replied 2 years ago.

Always has some gas in it. Right now I'm draining the oil. Tomorrow I'll change oil (30W) and filter to see if the oil still smells like gas.

Expert:  Briggs-Fan replied 2 years ago.
This is a diagram of your carburetor, where the inlet needle goes most likely is a brass inlet valve , those wear out then gas bypasses the needle etc and will run down into the crankcase and mix with the oil
http://www.ereplacementparts.com/kawasaki-fh430vas35-stroke-engine-parts-c-30157_30211_31200.html
Customer: replied 2 years ago.

Changed oil (30W) and filter. Ran the mower for at least 30 minutes over half the time with blades engaged. There was no smoking during the 30 minutes except for 1 puff when the blades were engaged. Checked the oil after the run and my wife said there was a hint of gasoline smell in the oil.

Expert:  Briggs-Fan replied 2 years ago.
It confirms my suspicion, the carb is allowing gas to bypass the needle and inlet valve and get down in the crankcase and mix with the oil. Don't run it until it's fixed because it can lock the motor up or break the connecting rod. The carburetor will have to be removed and rebuilt completely, meaning that the brass inlet valve that is pressed in to the carburetor has to be changed along with the needle etc . What happens is when the brass inlet valves wear out they don't seal with the needle and as a result the float closes the gas on tines to flow coming up through the carburetor and then running into the crankcase. After the carburetor is rebuilt change the oil and it will be fine .
Expert:  Briggs-Fan replied 2 years ago.
Hi did you get a chance to rebuild the carburetor and replace the inlet valve ? . If not it will keep allowing gas into the crank case and damage the engine
Customer: replied 2 years ago.

I have ordered a new carburetor and fuel pump which will be here tomorrow. In addition I'm going to install a fuel cutoff valve. I have no plans on running the engine until I've replaced the carb & fuel pump.

Expert:  Briggs-Fan replied 2 years ago.
Ok , don't change the oil until the new stuff is on. Also let me know how that goes . Also once it's fixed etc please don't forget to accept and rate my answer so I get credited with helping you.
John
Customer: replied 2 years ago.

I drained the carburetor, disconnected the fuel pump then changed the oil. I'll check the oil for odor before I start the engine.

Expert:  Briggs-Fan replied 2 years ago.
Ok , I'll wait to hear back from you once you get it together
Customer: replied 2 years ago.

OK. There's good news & bad news. After changing the carb & fuel pump I mowed the yard (1 1/2-2 hours). Very little smoking. Drained a little oil and my wife says there is no gas smell. I decided to check the spark plugs. One of them was fine. The other had a black oily accumulation on it. The area around the plug was caked with oily dirt. Another problem? Attached is a picture of the plugs.

If another consultation fee is required that's OK.

Expert:  Briggs-Fan replied 2 years ago.
Are these both new plugs ? If not , clean or replace them and see if it keeps doing it . It could be from the past before the carb issue was fixed
Customer: replied 2 years ago.

They are not new. Probably 1 year old. I'll replace them.

Expert:  Briggs-Fan replied 2 years ago.
Ok before we diagnose any issue , let's see how new plugs do , the gas in the oil before would cause that
Customer: replied 2 years ago.

Will do. Can't understand why one would foul but not the other. I'll give it a go.

Expert:  Briggs-Fan replied 2 years ago.
Let's see how the new plugs do , there's a few things that could cause it if it keeps up. The head gasket, ring etc , . Is there oil caked around the head etc ? .
Customer: replied 2 years ago.

There was something caked around the plug. I'll take the cover off tomorrow and have a better look.

Expert:  Briggs-Fan replied 2 years ago.
Ok I'll wait to hear back from you , it may just need a gasket
Customer: replied 2 years ago.

Took engine cover off today, there was oil/dirt mixture all around the fouled plug. Replaced both plugs and ran about 30 minutes. There was minor smoking (hard to see in Houston atmosphere). Pulled the suspect plug and there were black deposits on it. The other plug was clean. I'm up for trying things within my level of expertise. From what I've read replacing piston rings is outside my area.

Expert:  Briggs-Fan replied 2 years ago.
Could be the valve clearance too. Let me check valve clearance specs for you
Expert:  Briggs-Fan replied 2 years ago.
If its around the head on the outside it sounds like a bad head gasket .
Customer: replied 2 years ago.

The junk was around the spark plug and below it. By all appearances it looks like the oil leaked from around the spark plug which I don't think is possible. There was a lot of it -- really thick like maybe 1/4 inch.

Expert:  Briggs-Fan replied 2 years ago.
It shouldn't leak around the plug at all, is that where it's coming from
Customer: replied 2 years ago.

The junk was caked around the plug and continued down to the fins. I didn't find any of the junk much higher then the top of the plug. It "appeared" that the leak was from the plug.

Expert:  Briggs-Fan replied 2 years ago.
Was the plug loose ? That's not good , it could be the head if the spark plug hole is letting stuff get by it .
Customer: replied 2 years ago.

No. The plug was not loose.

Expert:  Briggs-Fan replied 2 years ago.
Nothing should be getting around that plug , is it still ?
Customer: replied 2 years ago.

I'll check today. Once I get the engine & cylinder covers off to check, is there some pressure test to run?

Expert:  Briggs-Fan replied 2 years ago.
Yes you can do a leak down test on it like this
https://youtu.be/dsuhkzZXywU
Customer: replied 2 years ago.

Going to order leak down tester. Is there any problem running engine the way it is with frequent oil level checks. This afternoon I'm going to check the suspect cylinder head again to check externally for leaks.

Expert:  Briggs-Fan replied 2 years ago.
Harbor freight has them , I would be careful you do not want air being sucked into that cylinder
Customer: replied 2 years ago.

Received leak down tester. Ran the test on both cylinders. The results were virtually identical. The dial showed both well in the green range around 20%. I could hear air coming from the oil reservoir in both cases. Not that it makes any difference, the cylinder bottom in the "suspect" cylinder is brown while the other is black. Further thoughts?

Expert:  Briggs-Fan replied 2 years ago.
Well it shows the head isn't leaking and neither is the spark plug hole. It could be from the bad gas oil mix. It might take a while before it cleans up
Customer: replied 2 years ago.

I'll put it back together and mow as normal Monday or Tuesday.

Expert:  Briggs-Fan replied 2 years ago.
I would , just check the oil to make sure there's no gas odor etc
Customer: replied 2 years ago.

Decided to rerun leak down test while the engine was at operating temperature. Checked the suspect cylinder first & significant leakage with air coming out of carb. Tested the other cylinder again & it was good. Went back to retest the suspect cylinder. When I hooked the air line to the tester, engine oil flowed freely out of the carb. I now have a real mess.

Expert:  Briggs-Fan replied 2 years ago.
It sounds like the intake valve was open and you pressurized oil up into the carb , when a motor gets hot the oil thins . The carburetor needs to be cleaned out now
Customer: replied 2 years ago.

The reason I did the leak down test again was the mower started to smoke when it heated up. Valve problem, head gasket or new mower?

Expert:  Briggs-Fan replied 2 years ago.
I'd look into a short block because we don't know the rings , valves etc until we take it apart , a short block may be the cheapest method
Customer: replied 2 years ago.

Thanks --- a new mower will fix it.

Expert:  Briggs-Fan replied 2 years ago.
I can price a short block for you
Customer: replied 2 years ago.

Thanks for your offer but I'm not interested in anything which requires pulling the engine off the mowing deck. Was hoping to fix the smoking without becoming an expert in small engines.

Expert:  Briggs-Fan replied 2 years ago.
Well , the best advice I can give is drain the oil and clean the carb up and put new oil in it and run it . It could need a valve adjustment etc .
Customer: replied 2 years ago.

I cleaned the carb and it started right up. I plan on mowing tomorrow to see how it does.

Expert:  Briggs-Fan replied 2 years ago.
Ok , just check that oil to see if there was any gas smell at all in it ?
Customer: replied 2 years ago.

Checked the oil no gas smell. Ran fine for 15-20 minutes then started smoking. No noticeable loss of power just looks like a BBQ pit.

Expert:  Briggs-Fan replied 2 years ago.
It sounds like a ring , it gets hot , the ring expands and oil is bypassing in to the exhaust
Customer: replied 2 years ago.

Maybe I can get through one last mow tomorrow, then get another mower next week.

Expert:  Briggs-Fan replied 2 years ago.
Riders are pricey. If it were me I'd call a local small engine shop and see if they had a used motor they could slap on. Most likely the mower running with the gas oil mix could of damaged the cylinder. I don't feel it's a head gasket because those will cake oil all on the deck where the engine mounts etc
Customer: replied 2 years ago.

This is the second engine for this mower already. Kawasaki no longer manufactures this engine. If I replace the engine no telling what else is ready to go on a 10 year old mower. Small engine shops in the area quote 6 weeks to look at anything (per my neighbor). It's probably time to get me a nice ZTR mower.

Expert:  Briggs-Fan replied 2 years ago.
Ok , I'm sorry this didn't turn out better , I'd try to sell it for 200 or so , someone will slap a motor in it