B&S engine
#1
Member
Thread Starter
Join Date: Nov 2007
Posts: 12
Upvotes: 0
Received 0 Upvotes
on
0 Posts
B&S engine
400707 122201 14 hp twin IC. I have a hard start problem when it is cold, once it starts it is fine. New starter , battery load tested fine. Does this engine have valve adjustment?
I am thinking of possible fuel pump rebuild kit also.
Mower is 17 years young and almost looks new
I am thinking of possible fuel pump rebuild kit also.
Mower is 17 years young and almost looks new
#2
Member
Join Date: Nov 2007
Location: NE Okla
Posts: 383
Upvotes: 0
Received 0 Upvotes
on
0 Posts
When you say 'hard start', this mean it turns over slow? or, just takes a while for it to fire ?? I'm assuming choke plate closes when choke cable pulled out ??
If carb hasn't been rebuilt before the fuel pump diaphragms are probably stiff.
Is this on a Murray ??
thanks,
If carb hasn't been rebuilt before the fuel pump diaphragms are probably stiff.
Is this on a Murray ??
thanks,
#3
Member
Thread Starter
Join Date: Nov 2007
Posts: 12
Upvotes: 0
Received 0 Upvotes
on
0 Posts
hard start
it is a MTD product and it spins over slowly and it needs to jump start to spin over at the normal rate to start, when warm it spins fine.The electrical system has been checked amnd is fine. Does this motor have adjustable valves?
During the summer I do not have this problem only in the fall [cooler weather]
During the summer I do not have this problem only in the fall [cooler weather]
#4
Member
Join Date: Nov 2007
Posts: 97
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Continuing to jump it will eventually, and may already
have damaged the starter, so you need to address the
main problem soon. Once it has been started, the oil is warm
the battery has had a fresh jolt from the charging system/
jump, etc.
The battery may still be a little suspect, the "load"
test is not totally conclusive. The starter could probably
use a little disassembly and cleaning, that may help.
But the first thing I would do is remove both heads and
clean all of the carbon buildup from the top of the piston
and cumbustion chamber of the head. Older engines had
head gaskets that could easily be reused, with the newer style, sometimes you can get lucky.
Fish
have damaged the starter, so you need to address the
main problem soon. Once it has been started, the oil is warm
the battery has had a fresh jolt from the charging system/
jump, etc.
The battery may still be a little suspect, the "load"
test is not totally conclusive. The starter could probably
use a little disassembly and cleaning, that may help.
But the first thing I would do is remove both heads and
clean all of the carbon buildup from the top of the piston
and cumbustion chamber of the head. Older engines had
head gaskets that could easily be reused, with the newer style, sometimes you can get lucky.
Fish
#5
Member
Join Date: Feb 2006
Location: usa ohio
Posts: 112
Upvotes: 0
Received 0 Upvotes
on
0 Posts
it is a MTD product and it spins over slowly and it needs to jump start to spin over at the normal rate to start, when warm it spins fine.The electrical system has been checked amnd is fine. Does this motor have adjustable valves?
During the summer I do not have this problem only in the fall [cooler weather]
During the summer I do not have this problem only in the fall [cooler weather]
#6
Member
Join Date: Nov 2007
Posts: 97
Upvotes: 0
Received 0 Upvotes
on
0 Posts
and my suggestion is much simpler and cheaper. and the
valve adjustment is likely not the problem.
Fish
#7
Join Date: Apr 2004
Location: Upstate New York
Posts: 2,903
Upvotes: 0
Received 2 Upvotes
on
2 Posts
Most small engine have what is called a mechanical compression release (MCR) mechanism which is integral to the camshaft that, during starting RPM's, lifts a valve (or two valves on 2-cylinder engines) slightly and relieves some compression on the compression stroke of each piston. Just enough to allow the starter motor to spin the engine over easily. You have one of the very few engines that does not have this feature and, with such, you need a high amperage battery and good, clean starting circuit cable connections and a good starter motor. By design, boxer engines (opposed cylinders) are tough on starter motors, whether it be a small engine, mototcycle engine or automobile engine. I recommend a battery with a minumum of 375 cranking amps and make sure you have battery cables no less than 6 gauge wire. Another option is to install a heavy-duty starter motor and the Briggs part number for this is 498148 provided you have the physical room to install such, it is about one inch longer than the standard starter. FYI, the valve clearances are .005", intake and .008", exhaust. Removal of the intake manifold/carburetor assembly is required to access the valve covers (breather assemblies) along with the cylinder heads, of course.
#8
Something that I've noticed on these opposed twins, especially older ones like yours, is the starter wear at the top bushing. The bushing wears away from the flywheel (from the pressure of the gear forcing away from the flywheel during cranking). This is ok until it gets bad enough that the armature begins to scrub on the field magnets. This causes excessive resistance and makes the starter drag. I've seen this happen pretty often, and it's not hard to check. The bushing can be replaced, or the entire top cap of the starter can be replaced with new bushing included. When this is done, it would definitely be good to clean the starter, replace brushes or the brush cap if needed, clean the commutator, and apply a small amount of white lube to the bushing areas on the armature during reassembly. Make sure to be sparing with the lube. (not so much that it slings out and gets on the brushes when the starter spins).
Valves on a flathead may eventually need adjusting, but I doubt that's your problem because the valves on a flathead, by design, wear in such a way that would probably ease cranking, rather than make it more difficult.
Valves on a flathead may eventually need adjusting, but I doubt that's your problem because the valves on a flathead, by design, wear in such a way that would probably ease cranking, rather than make it more difficult.
#10
Member
Join Date: Nov 2007
Location: NE Okla
Posts: 383
Upvotes: 0
Received 0 Upvotes
on
0 Posts
I cured a slow, nostart cond on an old Craftsman GT earlier this year by cleaning all battery and solenoid connections, even batt neg cable conx to frame. symptom was ammeter showed discharge when ele clutch engaged.
After thorough brushing/cleaning, worked great.
What weight oil you using ??
thanks,
After thorough brushing/cleaning, worked great.
What weight oil you using ??
thanks,
#12
Join Date: Apr 2004
Location: Upstate New York
Posts: 2,903
Upvotes: 0
Received 2 Upvotes
on
2 Posts
Of course fuel in the oil will generate excess fluid in the crankcase and then create higher crankcase pressure. Do you smell fuel in the oil? If so, this will be caused by a faulty carburetor inlet needle & seat and/or a float that no longer floats due to gas in the float. Have you checked all six battery cable ends? How strong a battery do you have?
#13
I see the mention of the new starter in your original post now. I guess I skim through these posts too fast sometimes.
Question, does it blow a good cloud of smoke when it cranks up?
Question, does it blow a good cloud of smoke when it cranks up?