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Old 01 December 2008, 11:25   #31
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if you are going to start pitching up the prop you need to be careful!
With the standard pitch youre unlikely to cook anything as the engine will run out of RPM before it runs out of power(boat unloaded), once you start to increace the pitch, this will load the engine up more, and if the fuel screw is wound out too far to achieve enough power to get the RPM the same with the coarser prop then the EGTs will be rising, you could melt your turbo.
you have two choices now you have found the problem,
1 adjust the fuel screw so the black smoke is just visible under acceleration once the boost has started to build and leave it alone.
2 fit an exhaust gas pyrometer and run at below max allowable EGT for the turbo and re pitch the prop accordingly to achieve the max speed at a sensible combination of RPM and EGT. then-when it blows up(which it will, when you least expect it and at the most inconvienent time)
fit a yanmar!
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Old 01 December 2008, 15:47   #32
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Went for a quick run before the boat was laid up for the winter for other maintainance items and she was running a treat oil pressure 5bar - gearbox 3bar and temprature 75-80 cel
could go up on the pitch but slow manovering is a total pain as it is without compounding the issue,just getting used to the boat i suppose
Still got original setting 2 turns out on fuel screw and 2 on max rpm

Many thanks for the info on all the posts regarding the Pac 22

Will keep you posted on developments and upgrades as we go
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Old 02 December 2008, 14:50   #33
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thats the problem when you only have 1800RPM between tickover and Max rpm, i think this is why the yanmar engines are popular, they have an extra 1000RPM on tap so you can use standard srern power 101 gearing and prop.
good to hear its running as well as a Pac 22 can with that engine, you must be chuffed the engine and turbo wernt a problem!
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Old 02 December 2008, 18:57   #34
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Doggypaddle, The yanmar setup does not utilise the same ratio in the leg. The mermaid uses a 1.32:1 and the yanmar uses 1.66:1 hence when you get a yanmar version it does not go exceptionally faster.

Ok it revs up to 3500 + but that is reduced so the input to the prop will be nearly the same.

The yanmars were mainly made 160 hp - 180 hp so for power they are very similar to the mermaid. Where they score is weight.

I have had a yamaha 240 hp put in my second P22 and retained the 1.32 ratio from the mermaid. I think its the fastest one out there !

AMAC : Try and get the tickover speed quite low for manouvering in a marina, and dont be afraid to give it a bit of grunt in and out of reverse when going alongside. Once you have the hang of it they may be better than a single O/B for manoevering.

Unfortunately the mermaids will always have a bit of black smoke. They have an ancient design of fuel pump which just pumps in as much fuel as possible to make the thing go faster. When at a standstill or going slowly, they will under cool and be more prone to smoking. When they are under load up on the plane they will be running at the correct temp and the smoke will disappear. The black smoke will be worse with no load with the fuel screw turned up.

Good luck ! JC.
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Old 03 December 2008, 07:35   #35
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pac22

Thats what i was getting at...yanmar engine and standard mermaid transmission and prop!
yep they are smokey old ford 6000 series tractor engines, bloody good though!
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Old 03 December 2008, 07:44   #36
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The black smoke will be worse with no load with the fuel screw turned up.


The black smoke will only be worse while under load and accelerating, once its got boost up it should be fairy smoke free.
the smoke screw makes no difference with no load, its only a rack stop on the minimec pump, the pump has no advance unit or compensator, hence they are optimised for use at near max rpm and boost, and so at low rpm and low boost it will run slightly more advanced than optimum and well overfuelled, hence the plumes of clag while the turbo plays catchup
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Old 05 December 2008, 11:50   #37
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Quote:
Originally Posted by doggypaddle View Post
the turbo wont stop it revving to the correct governed speed off load.

Sorry, I found this thread a bit late.
But, my mercruiser diesel suffered from a stuck open wastegate valve, and it would not rev above 1500 rpm, which equated to about six knots on the water.
I agree that in theory the engine should rev, but in my case it did not.

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Old 05 December 2008, 12:26   #38
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it wont rev if the wastegate sticks open, because the exhaust turbine is bypassed, therefore you will not get any boost, depending on whether or not the pump has a compensator you will either get low performance or low performance accompanied by loads of black smoke.
the wastegate occasionally sticks open on my landrover and i get no boost, its only a 2.0 engine and really needs the turbo, with the wastegate stuck i struggle to hold 65 on the flat
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Old 05 December 2008, 12:35   #39
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Quote:
Originally Posted by jackcastoff View Post
Try and get the tickover speed quite low for manouvering in a marina, and dont be afraid to give it a bit of grunt in and out of reverse when going alongside. Once you have the hang of it they may be better than a single O/B for manoevering.
They are deffinately more manouverable compared to an outboard, can be made to go sideways with practise and turn round in just over there own length.

Thought the engine was based on the Ford 2700 series.

Pete
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Old 05 December 2008, 16:56   #40
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Thought the engine was based on the Ford 2700 series.

Pete
I guess if you go back far enough and through enough mods the fordson thames 4D as in the trader and the major tractor? they certainly look very similar.
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