Briggs 18 hp twin very hard to turn over won't start

megaquark · 06-21-2008, 07:25 PM

OK. It was working fine until my wife ran it out of gas. I filled it up and she proceeded to try to start it and held the key turning the motor over for about a minute. After a while the turning got slower and slower until finally it wasn't turning over again. Thinking it was just the battery that went dead, we charged the battery but still no go. WHat I notice now is that the red wire going to the starter heats up while trying to start it. I get maybe a turn or two but it's like the starter is working way too hard to do this. Manually turning the motor over is VERY difficult. It turns easy to a point (can't tell if it is the top or bottom of travel) and then it is very very hard to turn past that point. If I can get it over it rolls over to the same point again as it goes around and is difficult to turn further again.

I'm pretty sure it's not the battery. Nor is it the starter. I don't think that the engine should be putting up this much resistance to the starter which is why the thing is getting hot. Any ideas on what would keep the motore from turning easily at the top (or bottom) of travel?

I got this mower free from someone after it had been sitting in a garage for about 3 years. After changing the basic maintenance items it has run fine - but turning over has always been a bit on the slow side as if there is some point as the thing turns that something is rubbing and keeping it from turning easily.

Any ideas?

**K-B** · 06-22-2008, 06:50 PM

Take the spark plug out, and try turning it. Still hard? Easy?

ColinRyan2 · 07-03-2008, 01:34 PM

is this an overhead valve engine. newer engines have high compression. they have a unit on the camshaft that opens the valves slightly on cranking to release some of that compression until that unit starts. It is more difficult to turn these engines over by hand.

If she cranked the engine to long it is possible that she could of damaged the starter, starter solenoid or the wires. The longer you crank the engine the more heat is made and resistance. this could cause winding in the starter or solenoid to melt. could cause wires to burn.

RakerBill · 08-23-2008, 09:38 PM

In my past experience with mower engines, especially used, or older ones, they can sometimes build up carbon on the pistons inside of the motor. When it was running, did the engine make any unusual noises like a knock, or rattle? Does it smoke at all? Either of these can be a telltale sign of buildup.
You should take the starter to a reputable small engine mechanic, and have it looked at to see if the starter is hanging up. They are not designed to take much abuse like extended cranking, as they will get hot fast. And also check both the battery cables on both ends to see if there is any corrosion, or if they are loose, as if there is, it will cause hard cranking, and the wires to heat up as well.

Fix · 09-23-2008, 11:24 AM

Adjust your Valve Clearance.

Tuna Man · 09-27-2008, 11:53 AM

Valve adjustment on overhead valve engines...There is a torx set screw in the rocker arm nut (is on my 17.5hp). Losen it before adjusting valves. Also adjust valves when the piston is 1/4" after TDC. This is done because of the compression release arm on the cam.

06-21-2008, 07:25 PM	#1 (permalink)
megaquark Registered User Join Date: Jun 2008 Posts: 1 OS: win 2k	Briggs 18 hp twin very hard to turn over won't start OK. It was working fine until my wife ran it out of gas. I filled it up and she proceeded to try to start it and held the key turning the motor over for about a minute. After a while the turning got slower and slower until finally it wasn't turning over again. Thinking it was just the battery that went dead, we charged the battery but still no go. WHat I notice now is that the red wire going to the starter heats up while trying to start it. I get maybe a turn or two but it's like the starter is working way too hard to do this. Manually turning the motor over is VERY difficult. It turns easy to a point (can't tell if it is the top or bottom of travel) and then it is very very hard to turn past that point. If I can get it over it rolls over to the same point again as it goes around and is difficult to turn further again. I'm pretty sure it's not the battery. Nor is it the starter. I don't think that the engine should be putting up this much resistance to the starter which is why the thing is getting hot. Any ideas on what would keep the motore from turning easily at the top (or bottom) of travel? I got this mower free from someone after it had been sitting in a garage for about 3 years. After changing the basic maintenance items it has run fine - but turning over has always been a bit on the slow side as if there is some point as the thing turns that something is rubbing and keeping it from turning easily. Any ideas?

06-22-2008, 06:50 PM	#2 (permalink)
K-B Moderator/Gearhead Join Date: Oct 2005 Location: NY Posts: 2,725 OS: Ubuntu 8.04 My System	Re: Briggs 18 hp twin very hard to turn over won't start Take the spark plug out, and try turning it. Still hard? Easy? __________________ Registered Linux User #435503 Don't let socialists take over this country. Vote Nobama 2008!

07-03-2008, 01:34 PM	#3 (permalink)
ColinRyan2 Registered User Join Date: Jul 2008 Posts: 21 OS: vista	Re: Briggs 18 hp twin very hard to turn over won't start is this an overhead valve engine. newer engines have high compression. they have a unit on the camshaft that opens the valves slightly on cranking to release some of that compression until that unit starts. It is more difficult to turn these engines over by hand. If she cranked the engine to long it is possible that she could of damaged the starter, starter solenoid or the wires. The longer you crank the engine the more heat is made and resistance. this could cause winding in the starter or solenoid to melt. could cause wires to burn.

08-23-2008, 09:38 PM	#4 (permalink)
RakerBill Registered User Join Date: Aug 2008 Posts: 11 OS: Vista Home Premium	Re: Briggs 18 hp twin very hard to turn over won't start In my past experience with mower engines, especially used, or older ones, they can sometimes build up carbon on the pistons inside of the motor. When it was running, did the engine make any unusual noises like a knock, or rattle? Does it smoke at all? Either of these can be a telltale sign of buildup. You should take the starter to a reputable small engine mechanic, and have it looked at to see if the starter is hanging up. They are not designed to take much abuse like extended cranking, as they will get hot fast. And also check both the battery cables on both ends to see if there is any corrosion, or if they are loose, as if there is, it will cause hard cranking, and the wires to heat up as well.

09-23-2008, 11:24 AM	#5 (permalink)
Fix Registered User Join Date: Sep 2008 Posts: 10 OS: xp	Re: Briggs 18 hp twin very hard to turn over won't start Adjust your Valve Clearance.

09-27-2008, 11:53 AM	#6 (permalink)
Tuna Man Registered User Join Date: Sep 2008 Posts: 3 OS: xp	Re: Briggs 18 hp twin very hard to turn over won't start Valve adjustment on overhead valve engines...There is a torx set screw in the rocker arm nut (is on my 17.5hp). Losen it before adjusting valves. Also adjust valves when the piston is 1/4" after TDC. This is done because of the compression release arm on the cam.