I know this isn't a boat , but

[Big Dave]

I know this isn't a boat problem, but My neighbor had trouble with his ridding mower starting. 18.5 hp briggs and stration engine. Charged the batt. checked the starter it still wouldn't start. Tried jumping with extra batt still the same. When cranking it was like the starter didn't have power to crank it over on the compression stroke. Cleaned all the wire ends and still the same. Found a vidio online that solved the problem. It seems that the overhead valve briggs and stration engines have trouble with the valves adjustment backing off. Adjusting the valves solved the problem. Everyone was treating the symtoms and not the real problem . Just something to think about when trying to fix our boat problems. Find the real culpert.

[adirondackice]

I have the same exact problem right now....finally got it started, guess it was the engine de-compression valve...was told by a mechanic that this is most likely caused by dirty oil ...lack of oil changes....yeah that sounds about right in my case, I was buying a house and moving, and didnt give it the attention it should have! He also said these de-compression valves can be freed up by dumping some kero in the oil fill! Mine got freed up when it was 95 degrees out for a week and I just happened to try to start it. Was a very frustrating spring because like your neighbor, I tore the whole thing apart, bought a new battery, check solenoid, check starter......ended up buying a new mower which is ok but I wish I didnt have to....

[Tim Bromund]

Sounds like it needs some muffler bearing grease

Tim

[Big Dave]

I have the same exact problem right now....finally got it started, guess it was the engine de-compression valve...was told by a mechanic that this is most likely caused by dirty oil ...lack of oil changes....yeah that sounds about right in my case, I was buying a house and moving, and didnt give it the attention it should have! He also said these de-compression valves can be freed up by dumping some kero in the oil fill! Mine got freed up when it was 95 degrees out for a week and I just happened to try to start it. Was a very frustrating spring because like your neighbor, I tore the whole thing apart, bought a new battery, check solenoid, check starter......ended up buying a new mower which is ok but I wish I didnt have to....

Thats just what was going on with the neighbors mower . All it was , was the valve adjustment.. the decompression valve works off the valves. If they are out of adjustment , it can't work. It was easier to adj the valves than pull the starter off.

[Big Dave]

Had to fix it for him. He dosen't like the way I mow the front lawn. So he mows it all summer . Gives me more time to fish