Hot Topics: Slow Driving Lawn Mower

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Original Post: Lawn Mower Power Lack

Slimshaky member

I have a Simplicity Regent ride-on lawn mower (2690437) with a 20hp briggs intek v-twin engine. It currently shows a lack of power and the engine doesn’t sound like it’s running smoothly. When it comes to power, pressing the accelerator pedal slows down the throttle than it used to. I’m not an expert on engine noises, but the engine maybe making a little pinging noise or bad ignition.

 

So far this season, he changed the oil, the spark plugs, and replaced a worn drive belt. However, none of these seem to make a difference in the lack of power. We also confirmed that both plugs are sparking, although I’m not a great judge of how strong the spark is.

Danish Driver Group Moderator

Are both cylinders firing?

When you replaced the spark plugs, what did the old ones look like?

Slimshaky member

How do I know if both cylinders are firing?

The ends of both plugs were black and at least one of them appeared to have some oil on it. I decided to check the oil level at the time, and it was within the ideal zone.

BFHFixit

Make sure your choke is working properly.

Slimshaky member

In terms of the choke, I can confirm that opening and closing makes a difference in the operation of the engine, as I have to adjust every time I do a cold start on the mower. Am I correct in assuming that this would be a good indicator that it is working properly?

Danish Driver Group Moderator

Are you smoking the exhaust? If so, and with the spark plug covered in oil, I would put a bottom seal on the list of possible causes.

Slimshaky member

I think it smokes a little when I turn on the mower, but not after that.

Danish Driver Group Moderator

Check for sparks in both cylinders. If you both have a spark, they would look for other signs that you might have a broken head gasket. If that’s all, it’s a pretty inexpensive repair.

Member geogrubb

I don’t see where the engine was confirmed to be running on both cylinders. Start and remove a spark plug wire. If the engine tempo changes / starts to misfire, that cylinder is firing. Then test it on the other cylinder. Have a good.

Geo

Slimshaky member

Thanks for the detailed instructions. Now confirmed that the engine works with both cylinders.

Slimshaky member

Is there anything I should check with the head gasket below? I will say that I am not noticing constant smoking as I saw in various videos demonstrating symptoms of a failed head gasket.

Danish Driver Group Moderator

Read a bit online. There are many different symptoms such as smoke, dirty spark plugs, oil in the spark plugs, more than the usual amount of oil that is injected into the air filter housing.

I don’t remember you changed the air filter. Have you done that? A clogged air filter can rob energy.

Slimshaky member

The air filter looks a bit dusty, but it’s not too bad to look at. I turned on the mower, let it run for a minute, and then removed the air filter. It made no difference in terms of how the engine works.

Slimshaky member

Someone I know recommended that I do a compression test. I did it earlier today and found that the left cylinder is 140 psi. The right cylinder has 130 psi. Sounds reasonable for this type of engine? I don’t think I’ve mentioned this before so the engine number is 406577.

cheese forum topic moderator

Those numbers are great. What color is the smoke? Have you checked the valves and their settings?

Slimshaky member

I double-checked to be sure about the smoke item. When I first turn on the mower, there is a fairly strong exhaust smell, but there is no smoke at the moment. Perhaps this is quite normal.

I haven’t looked at the valves. Do you have a recommended video or instructions for that?

cheese forum topic moderator

I would start by removing the valve caps and making sure the available pushrods and rocker arms are in place and not loose.

Slimshaky member

This is yet another demonstration of my ignorance on this subject, but after further research, the noise I was hearing and believing the provenance of the engine resulted in the actually detected transmission area. After doing some more research, I am looking to change the transmission oil.

Also, you noticed that there is another belt that has the beginning of a tear. I am planning to replace it. The part number is 1728008 with a description of “V-BELT, Drive Belt, Aramid / Kevlar.” I don’t know if this is normal, but I also notice that it is quite loose.

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