motor siezed while running,,WHY?HELP!!!
 

My starboard 454 mag with unknown hours locked up while running 4000 rpm.Pulled the Seawater pump,looks good. Of course I'll pull the pan and check the pump but it seems it overheated and had oil? Seems unlikely a plastic bag or something wrapped around the outdrive because SW pump is alive. I have spun bearings before but the motor will still run. Any ideas before I put the new Mtr in and possibly toast it. No alarms and it happened in about 15 secs so I didn't get to watch the gauges. But water press had been running 30 psi at wide open. If my oil pump didn't die I'll be stumped. Any ideas? Don't the rings get oil from the crank slinging oil?Plugs look great not fuel washed not lean.HELP!If a head gasket blew and put a little water in a cyl could that do it?I took the plugs out and it is locked tight!

Re: motor siezed while running,,WHY?HELP!!!
 

could be a broken crank! just my 2cents

Re: motor siezed while running,,WHY?HELP!!!
 

Outdrive locked up?

Re: motor siezed while running,,WHY?HELP!!!
 

Drive or mains.

Re: motor siezed while running,,WHY?HELP!!!
 

mtr is for SURE locked,all the plugs out won't budge. I hope it's oil related but will mains cause a running 4000rpm mtr to stop?

Re: motor siezed while running,,WHY?HELP!!!
 

i broke a drive and locked the motor, pull the drive and make sure it is the motor.

Re: motor siezed while running,,WHY?HELP!!!
 

I agree.....this should be step #1

Re: motor siezed while running,,WHY?HELP!!!
 

This Same Thing Happen To Me Last Week On 1 Of My 454's Ho. Was Running Great Then Just Locked Up Without Any Warning At All. Bidge Full Of Oil But No Holes Or Signs Of Leaks In Motor When Pulled. Can't Figure Out Why. Pulled All Plugs Motor Locked Up Solid. I Just Heard A Rumor That Doesn't Make Much Sense To Me. That Champion Spark Plugs Has A Croos Reference In There Books For A Certain Plug Size But There Was A Recall That Merc Dealers Are Suppose To Know About That These Plugs Are Causing 454's To Blow. Just A Rumor At This Time I Quess No Hard Facts Yet.

Re: motor siezed while running,,WHY?HELP!!!
 

step 1

Re: motor siezed while running,,WHY?HELP!!!
 

pull valve covers and plugs,check for dropped valve or possibly a cylinder full of water.

Re: motor siezed while running,,WHY?HELP!!!
 

For Sure !!!.............Then...Pull plugs & try to crank

Re: motor siezed while running,,WHY?HELP!!!
 

Cut the filter open also and look for debris.

Re: motor siezed while running,,WHY?HELP!!!
 

Everytime that happens to me it is a dropped valve. The dropped valve also results in a smashed spark plug though and it sounds like all your plugs check out ok. Make sure to compare the plugs closely and look for any that are steam cleaned. Tuliped exhaust valve can suck enough water to break things internally (rods) yet due the loud exhaust make it seem like a silent failure. Of course, removing the drive and cranking is the first order of business. Tomorrow I start the assembly process on my sb engine that lost a valve two weekends ago... you are not alone :mad:

BT :cool:

Re: motor siezed while running,,WHY?HELP!!!
 

mtr is out of boat,plugs out of mtr,it is locked tight. I will tear down soon while building my roller mtr. Every time it breaks it's gonna get faster!That'll show it!

Re: motor siezed while running,,WHY?HELP!!!
 

See, there is a silver lining in every cloud!

Re: motor siezed while running,,WHY?HELP!!!
 

It sounds as though you have broken a crankshaft my friend. Sorry to hear it.

Re: motor siezed while running,,WHY?HELP!!!
 

I had the same problem, running 4500 RPM's motor locked up. Reason for locking up was obvious, ( rod sticking out the side of the pan ) fiding the true cause is another story. It was a fresh rebuilt motor, this sucks !

Re: motor siezed while running,,WHY?HELP!!!
 

Ihad the same problem once... starboard motor locked up at about 4500 rpm... no warning ... no alarm.... this is what I found inside..... :cool:

Re: motor siezed while running,,WHY?HELP!!!
 

The reason for the failure was the remotely mounted oil filter was plumbed backwards.... Here is a picture of the mechanic that did the work...... :D

Re: motor siezed while running,,WHY?HELP!!!
 

i still say crank shaft!