Yanmar YSE12 low power

[happynelly]

Yanmar YSE12 – Swin Ranger 22 M/S
My trusty old Yanmar appears to be developing a problem.
After running at cruise of 4kts for around and hour RPM reduces, speed also fell back to around 2.5kts, noted steam (white smoke) from exhaust. Water discharge normal. Ran for the nearest shoreline and went aground, noted lots of weed around prop, clean off had a scrap of the hull, waited for the tide, magic 5kts before blackish smoke (she's and old girl)
Ho HO I though weed was causing the problem and making the engine work hard.
All was well for a couple of weeks then same problem, though this time on a flood tide. Had a poke around at the prop and rotated the shaft by hand all appeared clear. Started up again away she went no problem.
Does any one have any idea how to start trouble shooting this sort of problem.?
It is apparent that what ever is the cause requires the engine to work much harder to get the same prop RPM.
I am going to try and clean the injector and pump if I can find the data, also I will try a shot of cleaner in the fuel. I understand that there is a needle valve in the vanmar injector pump that does fail, could this be the cause of my problem?
I ideas and suggestions (other than spending large amounts of dosh) would be much appreciated as I don’t like this motorsailing backwards lark.
Neil




<hr width=100% size=1>

 

[bigmart]

I would guess that you're starting to overheat. I expect the waterways in your block are starting to fur up & this is the cause. I let my YSB12 get low on oil once & had a similar problem. luckily a refil with new oil & she seemed OK. There are ways of cleaning out the engine but I'm not expert enough to advise on that one. Perhaps someone else can help?

Martin

<hr width=100% size=1>

 

[sailorman]

if u remove the injector u will req. a new "polo-mint" seal that goes between the head & injector ( these r one use only)
i had a yse 12 & if u looked at the exhaust u could tell when the thermostat opened as white "steam / hotter water" was visiblle every-so -often.
i dont think the pump is servisable

<hr width=100% size=1>

 

[l'escargot]

Lots of answers <A target="_blank" HREF=http://www.yanmarhelp.com/>here</A>, especially the forum where you can post specific questions like yours.

<hr width=100% size=1>

 

[Rick]

Neil - suggest you visit the Thorensen Marine site in the US - they are Yanmar specialists, and their user forum area is tops for Yanmar info.

<hr width=100% size=1>