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Looking at a boat with twin Saltwater Series 150 OB

M

mdscole

New member
I'm looking at picking up a 1998 used boat with original Yamaha counter rotating outboard 150 hp Saltwater series engines. Claim of 450 hours.

The part numbers are
S150TXRW
S150TLRW

I get that the codes are:
S=Saltwater Series
150=HP
T=High Thrust
X=Standard rotation
L=Counter rotation
R=Remote
W=1998 year

I had a V4 Johnson 115 in 1995 on a four winns. It was terrible. It ate rings. So I'm leery of two strokes...but the newer four strokes push this boat out of my financial range.

Questions:

How do I keep it from eating piston rings? Is that a Johnson thing? I see a regular reference to "Ring Free" - some sort of expensive magical potion you add to the fuel.
Are there common points of failure associated with these engines?
Anything to worry about on the lower unit?
Is there a particular oil that is the most effective? (I hate to start an oil war)
 
I assume these are the carb'd ones. If so, they are amongst the best carb'd 2 strokes ever made. Maybe the best. We have put 2000 hours+ on some of these engines without any issues. The only thing to be careful of with these engines is that are slightly weak in the wrist pins. Will never be an issue unless they are run badly overloaded. If the boat reaches good WOT rpm's with a normal load on then they should be absolutely fine. Correctly propped to reach max WOT rpm's those engines should burn around 16gh (60lph) at a 4000rpm cruise. They have no issues with eating rings etc and given clean fuel are about as reliable as any outboard can be. Do run Ring Free through every service, but don't panic if you can't for some reason. I pulled one of these down recently that had done 2300 hours with no Ring Free for the past 1000 hours and very little flushing (lives in salt water) for the same period (4 years). Engine had damaged a piston due to an oil pump issue. Other than the damage from the oil pump failure the engine was in amazing condition. No significant carbon buildup, no issues with blocked cooling passages etc. Not saying that you shouldn't flush or use Ring Free etc, just that these engines are tough and will handle a bit more rough use than many others will.
 
After experiencing their four strokes I have gone off Yamaha as a brand, but we have had 6 of those SWS2 engines at the 200hp, 175hp and 150hp ratings in a self drive hire fleet and they are about as good as it gets for ease of maintenance and reliability.
One thing when cold starting them is to make sure that the choke operates when you push the key in when in the ON position. You will hear the click from the engine. They need that choke for the first cold start each day, but after that should start perfectly all day without the choke. The other thing that they all seem to like at a cold start is a bit of throttle, so lift the fast idle lever until you have maybe 1/4 to 1/3 throttle for a cold start. Once you get the technique sorted they are usually very good starting engines, but if you don't use teh choke properly they can be frustrating when cold.
 
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