Yamaha 150HP Cylinder Head Removal

I started to winterize my 2004 150HP carbed Yamaha yesterday when I ran into a problem. I finished fogging the engine through the carburetors using Yamaha's fogging oil per instructions on the can. I saved a small amount in the can so that I spray the remainder directly into each of the cylinders. Here’s where my problem started. As I was spraying the fogging oil into the first cylinder, the spray nozzle extension that came with the can popped off and you guessed it--shot right into the cylinder. I bent a piece of small diameter wire with a hook on the end and was able to retrieve about a three inch piece of the nozzle extension. ( Don’t know why the nozzle extension would have separated.) I then tried to suck out the remaining piece with a vacuum cleaner with no luck. I figured my only other course of action was to remove the head. I removed all of the bolts attaching the head but the head won’t budge. Does Yamaha used some sort of adhesive sealer on the head gasket? My experience has been to tap the head and it pops off. Since the engine is still under warranty, I don’t want to apply a lot of pressure to the head and mar the finish. Any suggestions?

Re: Yamaha 150HP Cylinder Head Removal

It shouldn't be glued on ... unless somebody did it after the factory.

Re: Yamaha 150HP Cylinder Head Removal

the factory gasket has an adhesive/sealant, after double checking you have all the headbolts out you should see a small rectangular area to pry on or use a dead blow hammer and tap it sideways.<br /> if you have turned the crank since this started its most likly sheared the rest of the tube either in the exhaust or the intake port. use a 3M pad on a drill to remove all traces of the original gasket and coat the new gasket with perfect seal or BRP gasket maker.<br /> use the correct torque and sequence and it will go backtogether just fine. retorque at 10 hours. use pipe sealant with teflon on the bolt threads.<br /> its the 12mm headed bolts your removing not the 10mm headed ones.

Re: Yamaha 150HP Cylinder Head Removal

Thanks for the response Rodbolt. <br /><br />All 14 of the 12 mm head bolts are out. I tried prying with some pressure on the rectangular area you mentioned on top of the block/head. But I didn’t want to deform or mar any of the surfaces. I guess I wasn’t expecting the use of an adhesive on the gasket. I’ll try using more pressure in the morning, or as suggested , a dead blow hammer. What additional problems will I encounter if in fact the remaining piece dropped into the intake or exhaust port? I guess I’ll find out in the AM. I’ll report back tomorrow. <br /><br />Regards

Re: Yamaha 150HP Cylinder Head Removal

Rodbolt thanks for your help. The head come off with a little more force and a larger pry bar. That’s some strong adhesive Yamaha uses on the head gasket. I also found the remaining piece of nozzle in the intake port. I was able to get it out without too much difficulty. Am I interpreting you correctly that Yamaha parts doesn’t sell the same head gasket they use in the initial assembly. Is a similar aftermarket gasket available that has the adhesive applied?<br /><br />Regards

Re: Yamaha 150HP Cylinder Head Removal

it has a sealent on it, I just dont trust it much. if the block and head were freshly machined maybe, but in the field I always use perfect seal. the whole KEY is CLEANLINESS. the surfaces must be clean shiney and oil free. that means no finger prints either.<br /> use alcohol or acetone to wipe the surfaces just prior to assy.<br /> the service manual says its ok to use factory head gaskets with no sealer.

Re: Yamaha 150HP Cylinder Head Removal

Thanks again Rodbolt. Your a treasure.

Re: Yamaha 150HP Cylinder Head Removal

ask my exwife about that.<br /> some folks have differing opinions <br /> the 3m pads are avalible at wally world and work great, much better and safer than a wire brush and wire is not reccomended to use on aluminium anyway.