Explains a LOT

sailme88

sailme88

.
Jan 19, 2010
1,171
Catalina 34 Casco Bay
Three pics.. Today I had my Hurth transmission pulled out for either a rebuild or replacement. During the summer, I had noted soot water running across the top of the water muffler. Figured it was OEM and might need replacement. Ordered one from Catalina Direct in August ( still waiting for it). With the tranny out of the way, it seemed a good opportunity to remove the muffler. It might also be noted that anytime the RMPs were advanced beyond 2500 the engine would begin to overheat. The pics speak for themselves. At some point before I acquired the boat the hose clamps were tightened down to the point that they collapsed the fiberglass tank nipple. This restriction surely is responsible for overheating at higher RPMs. OYE..
IMG_9730.jpg
IMG_9732.jpg
IMG_9731.jpg
 
P

Project_Mayhem

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Sep 24, 2018
2,599
O'Day 25 Chicago
Sorry to hear your transmission went out. At least it the overheating issue was an easy find. I wonder if any engine manufacturers list flow rates and pressures for coolant to aid in diagnostics
 
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Tally Ho

Tally Ho

.
Jan 7, 2011
4,781
Oday 322 East Chicago, IN
@sailme88,

Did you notice any reduced flow out of the exhaust?

When I push my Yanmar 2GM20F hard, I get some black stuff (unburned fuel?) in the exhaust and the hi-temp alarm will eventually come on. Backing off the RPMs a little puts things back to normal. I am in fresh water, clean bottom, clean prop.

I suspect the mixing elbow, but haven’t replaced it yet. I had my muffler out over the summer, and it seemed clear and both inlet snd outlet looked clear.

Greg
 
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sailme88

sailme88

.
Jan 19, 2010
1,171
Catalina 34 Casco Bay
Tally Ho said:
@sailme88,

Did you notice any reduced flow out of the exhaust?

When I push my Yanmar 2GM20F hard, I get some black stuff (unburned fuel?) in the exhaust and the hi-temp alarm will eventually come on. Backing off the RPMs a little puts things back to normal. I am in fresh water, clean bottom, clean prop.

I suspect the mixing elbow, but haven’t replaced it yet. I had my muffler out over the summer, and it seemed clear and both inlet snd outlet looked clear.

Greg
Click to expand
the foot bone's connected to the ankle bone.... Had problems with the raw water pump. would lose prime and not even lift. I was chasing related issues over the past few years. There is light at the end of the tunnel. Either new of rebuilt tranny, NEW heat exchanger, NEW motor mounts, NEW raw water pump, NEW hoses all around and a NEW water muffler ....
 
DougM

DougM

.
Jul 24, 2005
2,242
Beneteau 323 Manistee, MI
Tally Ho said:
@sailme88,

Did you notice any reduced flow out of the exhaust?

When I push my Yanmar 2GM20F hard, I get some black stuff (unburned fuel?) in the exhaust and the hi-temp alarm will eventually come on. Backing off the RPMs a little puts things back to normal. I am in fresh water, clean bottom, clean prop.

I suspect the mixing elbow, but haven’t replaced it yet. I had my muffler out over the summer, and it seemed clear and both inlet snd outlet looked clear.

Greg
Click to expand
Greg,
The black smoke can also be a symptom of having an over pitched prop.
I had deliberately run a prop that was over pitched for a couple of years to try to get more reverse power,and had the smoking issue in forward at max hull speed. Dropped back two inches in pitch and the smoking disappeared.
I
 
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Tally Ho

Tally Ho

.
Jan 7, 2011
4,781
Oday 322 East Chicago, IN
DougM said:
Greg,
The black smoke can also be a symptom of having an over pitched prop.
I had deliberately run a prop that was over pitched for a couple of years to try to get more reverse power,and had the smoking issue in forward at max hull speed. Dropped back two inches in pitch and the smoking disappeared.
I
Click to expand
Thanks Doug.

I can reach hull speed easily enough at around 3,200 RPM. But if I open it WOT, I get the black soot in the exhaust.

I think it is the original prop, but I don’t know the history or maintenance. So probably a good idea to take it to a prop shop and let them have a look.

Happy New Year!

Greg
 
Tally Ho

Tally Ho

.
Jan 7, 2011
4,781
Oday 322 East Chicago, IN
sailme88 said:
the foot bone's connected to the ankle bone.... Had problems with the raw water pump. would lose prime and not even lift. I was chasing related issues over the past few years. There is light at the end of the tunnel. Either new of rebuilt tranny, NEW heat exchanger, NEW motor mounts, NEW raw water pump, NEW hoses all around and a NEW water muffler ....
Click to expand
She will be as good as new once you get done with her:)

Happy New Year,

Greg
 
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