[matt.schaefer86]

It really depends on what you are trying to accomplish.
For perspective
My 33 Tiara flybridge that I repowered with 6BTA 330hp.
2150rpm gets 20knots
2400 gets 24 knots
Full throttle 2910 29 knots

Boat weight dry factory specs is 12k.
In the sling with fuel and all the gear is 15k.

[matt.schaefer86]

(Your may need to install a boost gauge and a fuel PRESSURE gauge on the suspect engine to sort this out, or bypass the aneroid with a 20 PSI air pressure source to keep troubleshooting)

Tony
Can you describe this procedure of bypassing the Android?

[matt.schaefer86]

Tony
To clearly answer all questions

The throttle hits the stop 100%
Additionally the motor will hit 3200rpm in neutral

No Sync crap at all. 100% Mechanical

Literally no Smoke at all through the entire power band.

After coolers: these engines are ReMans and have approx 215 hours on them since started in the boat January 2020. They were supposed to have been rebuilt at the time as well.

I will have to get down there and get you a bunch of pictures.

[matt.schaefer86]

Tony
I went and ran the boat today. Fully loaded like the other day.
Prior to running I checked the drag guages on the SMX double doubles. It was at 5 well in the green.
I replaced the last chance fuel Filter
Checked the hoses and clamps on the charge tube. Had the exact same results. In the bay could get the motor in question to approx 2320rpm. The other side will continue to build RPM. Runs great and no smoke but the throttle lever reaches 2300rpm where you would expect it to but when you push it further it doesn’t try to make any more RPM.
Today in the bay and fully loaded at 2300 ish RPM the boat would make 21.5 knots

[matt.schaefer86]

Yes Rob of course 1850 was a typo. 2850 in March.
I typically don’t run around at full throttle.
When the conditions allow and I wanna run fast it is usually about 2400rpm. That gets us about 22-23 knots which is plenty fast on the pacific. Our usual cruise is 2150-2250 getting us 19-20 knots.

[matt.schaefer86]

Thanks for the reply tony
It made 1850 in March loaded very similarly to yesterday.

[matt.schaefer86]

Any advice on the steps to take?
I have done Rydlyme before and have done it like this. Can I follow the same flow with the pool acid mixture?

30 min circulation in forward(rydlyme flowing in the inlet and out the hose that would be hooked up to the exhaust)

Let sit 30 min

30 min circulation in reverse

Then button everything back up and start the motor and let it run for 15 min.

That sound right??

Thanks

[matt.schaefer86]

Should be as easy as that. You will reverse the cables at the helm binnacle.

[matt.schaefer86]

Thanks Tony for your thoughts. Hopefully these pics tell the story.

[matt.schaefer86]

There are twin disc in there now. The 3208 sit on a huge angle. I’m pretty sure the twin disc have no down angle. I think the Cummins are supposed to go In as close to flat as possible.

[matt.schaefer86]

Thanks for the replies. I didn’t know the ZF80a were not preferred. Not going to use those now. On the hunt for 220a now. This was very helpful!!

[Author]

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