1989 yamaha 150 head gasket replacement

Reelcs25

Recruit
Joined
Mar 26, 2009
Messages
4
How many hours of operations should the cylinder head gaskets be replaced?

Model:150 ETXF
HP:150 2 stroke
Hours: 500

Minor evidence of salt buildup between mating surface is present.

Thank you.

reelcs25
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 1989 yamaha 150 head gasket replacement

carefully inspect the plugs for signs of water.
problem with saltwater motors is age not hours.
if the gaskets are not leaking on a salt water use motor that old just keep the cooling system top notch and they will last many many years.
problem with trying to dissasemble a motor that old with salt water use is the broken fastener problem you may run into.
 

Reelcs25

Recruit
Joined
Mar 26, 2009
Messages
4
Re: 1989 yamaha 150 head gasket replacement

Engines are twins on a contender 25, both powerheads are in excellent condition. Compression is strong @120 lbs each cylinder with no delta (PSI). Plugs are burning perfect with no sign of water contamination.

Broken bolts ... you are not kidding .... been there .... done that ... I am replacing the steering arms and the shift shafts on both engines. Yes, I went through the cruling fiasco of having to cut through the adapter plates to cut through the bolts to free both powerheads.

The rest of the engine is in close to perfect condition, amazing. I ask about the head gaskets to take as much preventative maintenance precaution as possible without getting in deeper than I already am. I will be venturing way offshore and want to have some sense of security.

I was contemplating opting for repowering with DFIs but I do not have the budget right now, unfortunatley.

Estimated parts so far ~ $1,800.00.

Your thoughts!

Thank you for the prompt reply.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 1989 yamaha 150 head gasket replacement

if the engines are already on the bench then drilling out and tapping or heli-coiling is easy.
I may attempt it, I would be more concerned with the codition of the exhaust divider plate than the head gaskets but like I say once the powerhead is on the bench drilling is easy.
cause if the powerhead is mounted the only ones you will break are the ones that will require powerhead removal for drilling.
its murphy's law.
 

Reelcs25

Recruit
Joined
Mar 26, 2009
Messages
4
Re: 1989 yamaha 150 head gasket replacement

Why the exhaust divider plate? Would you prefer to use an impact or hand tools to attempt to remove head and or exhaust plate bolts? I will upload some pictures so you can assess and give me any more suggestion you may have to offer.

I appreciate it.

Thanks again.
 
Top