Gradually Overheating?

[Auto Doc's]

I am referring to the metal tins that surround the outer cylinder fins.

Much of this depends on how dusty the condition is when moving. Around my area there is a lot of loose sand and dirt, but people mow at full throttle, and it looks like a small tornado.

 

[Neo7]

I know you have removed the top shroud, but what about the cover tins over the cylinders to make sure they are not packed full of dirt and chaff? I've seen too many have a clean topside and the fins were packed solid.

As I recall, B&S had a number of overheat issues with this design.

Next idea is to go up one size on the carburetor main jets so it will richen the mixture slightly and help cool the combustion slightly. These engines were tuned to run super lean due to emissions imposed on the industry.

As for the transmission(s) they have cooling fins and usually cooling fans. The fans are common for rounding out the spline teeth in the center and gradually slip and lose cooling efficiency.

I’ve rebuilt a few of these engines but I’ve never seen those rocker cover tins full of dirt. Assuming the tins are fitted correctly How would the dirt get in there?

I am referring to the metal tins that surround the outer cylinder fins.

Much of this depends on how dusty the condition is when moving. Around my area there is a lot of loose sand and dirt, but people mow at full throttle, and it looks like a small tornado.

Oh Ok I get it now, sorry … No they are completely clear on my B&S engine

 

[Skippydiesel]

So have you checked out the thermocouples, as suggested in #15???

 

[Neo7]

I know you have removed the top shroud, but what about the cover tins over the cylinders to make sure they are not packed full of dirt and chaff? I've seen too many have a clean topside and the fins were packed solid.

As I recall, B&S had a number of overheat issues with this design.

Next idea is to go up one size on the carburetor main jets so it will richen the mixture slightly and help cool the combustion slightly. These engines were tuned to run super lean due to emissions imposed on the industry.

As for the transmission(s) they have cooling fins and usually cooling fans. The fans are common for rounding out the spline teeth in the center and gradually slip and lose cooling efficiency.

I’ve rebuilt a few of these engines but I’ve never seen those rocker cover tins full of dirt. Assuming the tins are fitted correctly How would the dirt get in there?

I am referring to the metal tins that surround the outer cylinder fins.

Much of this depends on how dusty the condition is when moving. Around my area there is a lot of loose sand and dirt, but people mow at full throttle, and it looks like a small tornado.

Oh Ok I get it now … no they are completely cl

So have you checked out the thermocouples, as suggested in #15???

No sorry Ive not had time to do that as I’m currently travelling.

 

[Neo7]

Oh right, I get what you mean now ... thanks for your thoughts on that.... But yes they were clear, maybe because I often use a compressed airline (over the whole engine), underneath those cylinders, where the exhaust pipes comes out.

I've been away from home for some time but next time I've mowed the lawn I intend to use my laser temperature checker all over the engine to see if I have any unusually high hot spots and also to double-check the readings I've been getting from the temperature sensor (thermocouples) I have on there atm.

 

[slomo]

Best to remove the lower tin shroud that surrounds the cooling fins and clean away. Really need a visual inspection to rule it out. Mice and critters can drag debris in there. And YES they clog up all the time.

 

[Neo7]

Best to remove the lower tin shroud that surrounds the cooling fins and clean away. Really need a visual inspection to rule it out. Mice and critters can drag debris in there. And YES they clog up all the time.

Yes, thanks again, all clear, for sure ... Actually, this same point has been coved two or three time now. I guess that's the problem with long threads like this one, because none of us have the time to read all the previous posts.

 

[Skippydiesel]

Follow up report?

 

[Neo7]

None yet, sorry

 

[Neo7]

Ok today I've compared the thermocouple measured temperature with the laser type temp tester. The thermocouple actually measured about 4 degC lower (rather than higher) but that was just midday temperature (with the engine not running), so maybe thermocouples inaccuracies are not constant from low to high temps.
Anyway, I changed the thermocouple and should be mowing the lawn in the next couple of days, so I'll report back after that.