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Briggs 18.5 twin specifications and hard to start when hot
#1
S
sbklf
S
sbklf
Hello from Houston,
I have a Huskee riding mower that I am working with an 18.5 Twin Briggs engine. I am just changing seals and gaskets to stop oil leaks, not sure which one is leaking so am changing all. The gasket kit came with different thicknesses of base gaskets for crankshaft end play adjustment (I am assuming). I measured before removing the base and was .017". What is it supposed to be?
What might cause the motor to be very hard to start after it gets hot? It seems if I adjust the throttle just right it might start back up 10% of the time but most of the time it wont, I have to let it cool first. I thought it might be the coil because the spark seems weak but the guy at Als says the coils either work or they dont, no inbetween.
Thanks, Kevin
I have a Huskee riding mower that I am working with an 18.5 Twin Briggs engine. I am just changing seals and gaskets to stop oil leaks, not sure which one is leaking so am changing all. The gasket kit came with different thicknesses of base gaskets for crankshaft end play adjustment (I am assuming). I measured before removing the base and was .017". What is it supposed to be?
What might cause the motor to be very hard to start after it gets hot? It seems if I adjust the throttle just right it might start back up 10% of the time but most of the time it wont, I have to let it cool first. I thought it might be the coil because the spark seems weak but the guy at Als says the coils either work or they dont, no inbetween.
Thanks, Kevin
#2
EngineMan
EngineMan
"What might cause the motor to be very hard to start after it gets hot?"
Poor choke (can also be over choking)
Poor valve clearance
Fuel (lack of fuel)
No spark
I can't answer your other question because I don't have the spec's for it.
Poor choke (can also be over choking)
Poor valve clearance
Fuel (lack of fuel)
No spark
I can't answer your other question because I don't have the spec's for it.
#4
S
sbklf
S
sbklf
Oh thanks, should have posted it orignally:
Huskee 18.5 Twin Briggs Model #42A707 Type: 1238-01 Code: 9702065B
I was able to download a "Check Chart" with some information but not sure I am looking at the correct columns.
-Is my engine considered an L head opposed twin cylinder?
-For the L head opposed twin cylinder, they show Model/Series options 400000, 420000 and 480000 (?), would mine fall under 420000?
Thank you, Kevin
Huskee 18.5 Twin Briggs Model #42A707 Type: 1238-01 Code: 9702065B
I was able to download a "Check Chart" with some information but not sure I am looking at the correct columns.
-Is my engine considered an L head opposed twin cylinder?
-For the L head opposed twin cylinder, they show Model/Series options 400000, 420000 and 480000 (?), would mine fall under 420000?
Thank you, Kevin
#5
EngineMan
question 1 yes it is a L head, question 2 that is the right column it should read 400000, 420000 and 460000
EngineMan
Oh thanks, should have posted it orignally:
Huskee 18.5 Twin Briggs Model #42A707 Type: 1238-01 Code: 9702065B
I was able to download a "Check Chart" with some information but not sure I am looking at the correct columns.
-Is my engine considered an L head opposed twin cylinder?
-For the L head opposed twin cylinder, they show Model/Series options 400000, 420000 and 480000 (?), would mine fall under 420000?
Thank you, Kevin
question 1 yes it is a L head, question 2 that is the right column it should read 400000, 420000 and 460000
#6
N
nbest
This sounds to me like the coil is going out. Heat increases the resistance so when the engine is hot and it is starting at a low speed it doesn't have enough voltage to overcome the resistance. You can test this by checking for spark the next time you have a problem. If it produces spark when grounded to the frame, but not to the plug, then the problem is the coil.
N
nbest
Hello from Houston,
I have a Huskee riding mower that I am working with an 18.5 Twin Briggs engine. I am just changing seals and gaskets to stop oil leaks, not sure which one is leaking so am changing all. The gasket kit came with different thicknesses of base gaskets for crankshaft end play adjustment (I am assuming). I measured before removing the base and was .017". What is it supposed to be?
What might cause the motor to be very hard to start after it gets hot? It seems if I adjust the throttle just right it might start back up 10% of the time but most of the time it wont, I have to let it cool first. I thought it might be the coil because the spark seems weak but the guy at Als says the coils either work or they dont, no inbetween.
Thanks, Kevin
This sounds to me like the coil is going out. Heat increases the resistance so when the engine is hot and it is starting at a low speed it doesn't have enough voltage to overcome the resistance. You can test this by checking for spark the next time you have a problem. If it produces spark when grounded to the frame, but not to the plug, then the problem is the coil.
#7
S
sbklf
Your right, it is 460000, had the wrong glasses on. Thanks
S
sbklf
question 1 yes it is a L head, question 2 that is the right column it should read 400000, 420000 and 460000
Your right, it is 460000, had the wrong glasses on. Thanks
#8
S
sbklf
I purchased one of those spark testers. When I get it back together I will test it.
S
sbklf
This sounds to me like the coil is going out. Heat increases the resistance so when the engine is hot and it is starting at a low speed it doesn't have enough voltage to overcome the resistance. You can test this by checking for spark the next time you have a problem. If it produces spark when grounded to the frame, but not to the plug, then the problem is the coil.
I purchased one of those spark testers. When I get it back together I will test it.
#9
Glenny65
I've heard people say that for 40 years, that a coil either works or doesn't. That is simply untrue. Coils can "fade" with time and cause problems when temperatures get too high. Everything from these opposed 180 Briggs engines, up to my 65 Ford Fairlane....(I always knew when my coil was about to go out because when I increased my rpm's it would start skipping. Fact is, (and you can google it too) the Briggs opposed engines are awesome in power/torque and smooth running, but they eat coils up pretty quick. Personally, I think it's because they fire twice as often as normal coils, but doesn't just cut the life in half, but by much more, since the double firing increases the heat. It was a bad idea, but aside from that, those engines are terrific. About the only thing you can do is make sure you set your air gap correctly...should be .010". And shine the surfaces that meet, both on the engine and the coil. This is to help the coil dissipate heat better. Also make sure the fins are clear of debris.....anything else you can think of to decrease heat from the engine.
Glenny65
Hello from Houston,
I have a Huskee riding mower that I am working with an 18.5 Twin Briggs engine. I am just changing seals and gaskets to stop oil leaks, not sure which one is leaking so am changing all. The gasket kit came with different thicknesses of base gaskets for crankshaft end play adjustment (I am assuming). I measured before removing the base and was .017". What is it supposed to be?
What might cause the motor to be very hard to start after it gets hot? It seems if I adjust the throttle just right it might start back up 10% of the time but most of the time it wont, I have to let it cool first. I thought it might be the coil because the spark seems weak but the guy at Als says the coils either work or they dont, no inbetween.
Thanks, Kevin
I've heard people say that for 40 years, that a coil either works or doesn't. That is simply untrue. Coils can "fade" with time and cause problems when temperatures get too high. Everything from these opposed 180 Briggs engines, up to my 65 Ford Fairlane....(I always knew when my coil was about to go out because when I increased my rpm's it would start skipping. Fact is, (and you can google it too) the Briggs opposed engines are awesome in power/torque and smooth running, but they eat coils up pretty quick. Personally, I think it's because they fire twice as often as normal coils, but doesn't just cut the life in half, but by much more, since the double firing increases the heat. It was a bad idea, but aside from that, those engines are terrific. About the only thing you can do is make sure you set your air gap correctly...should be .010". And shine the surfaces that meet, both on the engine and the coil. This is to help the coil dissipate heat better. Also make sure the fins are clear of debris.....anything else you can think of to decrease heat from the engine.
#10
I
ILENGINE
I have replaced maybe half a dozen of modules on the opposed twins in the last 20 years, so they are not any more problematic than the rest of the modules briggs or other brands. They fire two plugs on each revolution of the engine, but all the induction modules fire on all small engines every revolution be it briggs, kohler or kawasaki.
I
ILENGINE
I've heard people say that for 40 years, that a coil either works or doesn't. That is simply untrue. Coils can "fade" with time and cause problems when temperatures get too high. Everything from these opposed 180 Briggs engines, up to my 65 Ford Fairlane....(I always knew when my coil was about to go out because when I increased my rpm's it would start skipping. Fact is, (and you can google it too) the Briggs opposed engines are awesome in power/torque and smooth running, but they eat coils up pretty quick. Personally, I think it's because they fire twice as often as normal coils, but doesn't just cut the life in half, but by much more, since the double firing increases the heat. It was a bad idea, but aside from that, those engines are terrific. About the only thing you can do is make sure you set your air gap correctly...should be .010". And shine the surfaces that meet, both on the engine and the coil. This is to help the coil dissipate heat better. Also make sure the fins are clear of debris.....anything else you can think of to decrease heat from the engine.
I have replaced maybe half a dozen of modules on the opposed twins in the last 20 years, so they are not any more problematic than the rest of the modules briggs or other brands. They fire two plugs on each revolution of the engine, but all the induction modules fire on all small engines every revolution be it briggs, kohler or kawasaki.
#11
T
Tinkerer200
T
Tinkerer200
In my experience the opposed twin CDIs fail considerably more often then B&S singles or V twins which use 2 coils. First you might want to install a fuel line shut off and turn the gas off a few seconds before shutting the engine off. Or you can do this by clamping the fuel line. Sometimes fuel leaks on thru float needle flooding the engine until fuel evaporates off. On some of these engines the fuel line ran thru the cooling shroud causing vapor lock sometimes. I agree that the coil mounting surfaces need to be bright clean but to ground the coil properly not for heat transfer.
Coils do fail gradually sometimes. It is common on these opposed twins for failing coils to start an engine when one plug wire is disconnected, some say when that wire is then grounded to the engine. I have not experienced that. Might try it.
Walt Conner
Coils do fail gradually sometimes. It is common on these opposed twins for failing coils to start an engine when one plug wire is disconnected, some say when that wire is then grounded to the engine. I have not experienced that. Might try it.
Walt Conner
#12
Glenny65
I've had to replace many more than I could ever count or remember in the 10 years I've had a repair shop, though I rarely get them in anymore. I'm on my third on my own lawn tractor. I'm serious....google Briggs Opposed Twin coil problems. I'm glad you've had good luck with them, wish I did. And btw, the 20 HP coil, although it looks a little different, will swap out with the 15 HP perfectly. I've got a 15, and the last coil I installed was for a 20 and so far it's lasted longer than the 15's.
Glenny65
I have replaced maybe half a dozen of modules on the opposed twins in the last 20 years, so they are not any more problematic than the rest of the modules briggs or other brands. They fire two plugs on each revolution of the engine, but all the induction modules fire on all small engines every revolution be it briggs, kohler or kawasaki.
I've had to replace many more than I could ever count or remember in the 10 years I've had a repair shop, though I rarely get them in anymore. I'm on my third on my own lawn tractor. I'm serious....google Briggs Opposed Twin coil problems. I'm glad you've had good luck with them, wish I did. And btw, the 20 HP coil, although it looks a little different, will swap out with the 15 HP perfectly. I've got a 15, and the last coil I installed was for a 20 and so far it's lasted longer than the 15's.