Re: 1989 50hp force toque and sequence specs.for head?please help
Hi ForceFisher,
First - to level set the bases, I am not a marine mechanic. I am a retired electro-mechanical engineer/designer with a fair amount of hands on repair experience. I have never disassembled this motor to its internal components.
Second - for your reference, I am restoring a 16ft Blue Fin Spectrum model 1606JA with a 1989 Force 50Hp, model number 507Y9B, serial number 1561, 20" transom outboard. Your motor, same model as mine, is listed on the front page of my factory parts list as a Spectrum 1989 "B" model. Is your boat a Blue Fin Spectrum?
Third - Your questions in inverse order:
Head gasket part number: My factory part list "OB4275" is for the 1989 "B" model. It lists "Item 13 Gasket, cylinder head" as part number 691529. The head bolts, "Items 17 part number 2254, Screw, cylinder head and cover to cylinder" are 5/16 - 18 x 2-1/2. Again, my factory manual calls for a final torque of 270 in. lbs. for the 30 through 50Hp 1988 - 1991 models. No mention is made regarding different bolt sizes. I do also have the Clymer manual and see where Table 5 "Cylinder Head Bolt Torque Specifications" calls for 270 in. lbs. on 3/8" bolts and 225 in. lbs. on 5/16" bolts. What goes on there?
I called Mercury Marine and their support people checked for updates or errata on that manual. They verified the final torque value to be 270 in. lbs. as stated in the manual. If you are still concerned about the different answers go in the middle - 248 in. lbs. That is about the best I can do for you.
Water in block: I do not know if attempting to start and run the engine will purge the remaining water. I can see that water might have gotten into the transfer ports as well as the exhaust. The soot on the bolts is probably caused by exhaust getting around the bad head gasket. The manual does not specify any sealant or thread locker to be used during the installation of the head bolts. Lubricating the threads of a fastener will change the final impact of the torque. Did you check to see if the cylinder head was warped? Pretty much greater than 0.012" and it is Sushi. IMHO if the head is flat and gasket is installed and torqued properly you should not have any exhaust soot or water blow by.
If you must open the transfer or exhaust areas to clean and dry them you will need to acquire new gaskets to install as you reassemble the power unit.
Perhaps you could post some pictures of the problem areas then someone else on the forum may be better able to answer your questions than I.
Sorry about the delay in answering; I've been sick.
Good luck, Chris
this is how that looks in the book.
