Too many changes no baseline!

[pjcomeau]

I started the season with a new shaft, coupler, cutlass bearing, shaft seal, and Kiwi prop. When it when in the water I thought it was pretty noisy when in gear. I had never heard it before the changes (bought it in December), so I thought maybe it was the shaft seal. I did very little motoring, but the noise got worse and was determined the transmission was failing.

I ordered and had installed a refurbished transmission and when it came the mechanic thought there was a problem (It was stiff and would not turn by hand. It would also stall the engine when put in reverse). He knew that it would take a while to get a replacement and I wanted to leave for vacation (week long cruise with our club/fleet), so he installed it anyway. The stiffness seams to have improved, but I'm not sure.

I have to many changes and no baseline. I did not get the speed I expected from the Kiwi prop. Max RPM is lower then expected (~2600).

Assuming the tach is working, @ 2200 RPM I was getting 4.5 knots pulling an inflatable tender. Also, the mechanic was really concerned about max RPM in reverse. I just assumed it was the Kiwi prop. What should the max RPM be in reverse?

Until yesterday, I thought reverse power was more than adequate. But yesterday in heavy winds my reverse was very, very poor.

As mentioned earlier, I had never motored for any length of time until recently. Now when the engine is warm, the idle is much lower then when cold and If I bring the throttle all the way down, I stall the engine when I go to reverse.

I'm going to get someone to help me go through these issues. But any comments would be appreciated. I'm still not sure if I should keep the transmission (very labor expensive to pull out and get replacement again).

Someone mentioned, that if the tach is reading right at 2200 rpm, then the prop is my problem with speed. I had it set at the factory to 19 degrees (10 in pitch) as suggested by others. I did not confirm that it was set properly.

Thanks,

Pierre

[Steve Sayian]

Pierre,

With respect to the Kiwi: do you have the 16 inch or the 15 inch model?

I put one on last year and got the 16 inch diameter and it's too big.  I am going to get the blades exchanged for the 15 inch version.  I reset my pitch down to 17 degrees from 19 degrees and my M35 now gets the full 3000 RPMs it should have.

I also bought a laser tachometer from Harbor Freight ($49.00 USD) and re-calibrated my tachometer.  Very easy to do and I found out that the tach was over 1000 RPMs off!

There are other folks on the forum that have the Kiwi and are happy with it. 

Hope this helps,

Steve

[Rick Johnson]

Searching the web, I also found this one for a little less...

http://www.amazon.com/Digital-Laser-Photo-Tachometer-Non-Contact/dp/B000EUT9ZS/ref=pd_lpo_k2_dp_k2a_1_txt?pf_rd_p=304485601&pf_rd_s=lpo-top-stripe-2&pf_rd_t=201&pf_rd_i=B000RFK50S&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=16ZHJ1JCEC4N1CSBKRBR

[pjcomeau]

Thanks for the laser tach info. How do you use one of these? What do you point at? I'm going to check if anyone around has one.

I also got an email from a fellow owner from a club just up river whose been monitoring the forum suggesting I come and compare (look/listen) to his engine/rpm/speed...

Thanks,

Pierre

[Steve Sayian]

Pierre,

Very simple.
The lase tach comes with adhesive backed reflective strips. 
You place one on the crankshaft pulley, start the engine and point the laser tach at it and 'presto', instant RPMs. 
The one thing you have to do before placing the reflective strip on is to spray paint the surface of the face of the pulley with flat black paint.  Otherwise the tach will pick up background reflections and give you incorrect readings.

Steve

[prh77]

At 2200 I do about 4.5 kts. I max out at 3200 and 6.5 kts. Max prop set at 20 degrees. I can idle the engine down to 800 rpm and she goes into reverse with no problem. Did you buy this boat at Coneys in NY?

[pjcomeau]

Those speeds are closer to what I get (except I can't get past 2600-2800). There are previous threads that talk of speeds ~6 knots at lower RPM (2200-2400). Do you know what max RPM you get in reverse?

I did buy the boat at Coney's last December. Do you know anything about it's history?

My immediate concern is to determine if the transmission is as good as it gets (or close enough). The supplier has agreed to replace it if it's a problem, but the labor costs to get it removed (wait for the new one to come) and replaced is high enough to second guess.

Pierre

[prh77]

I never rev my engine above 1400 rpm in reverse, never seen the need. I looked at your boat at Coneys on 6/10/07 and understood there were some issues with the engine/transmission/fuel tank.

[pjcomeau]

Thanks Ron for the email. The 10" pitch was based on other Kiwi prop owners.

Last night was a really good night to go out and check some numbers as there was no wind and very little current (in between tides).

The numbers were much better then expected. After a week of pulling an inflatable tender (when comparing to last night, I was loosing around 1 knot, can you say dragging an anchor) and motoring 3 - 4 hours a day, I think everything got a good work out. The numbers are closer to some of the numbers reported by others (including other Kiwi owners in older posts I found).

I'm going to change the transmission fluid and see if it's still clean (only a few hours). If everything looks fine, then move on to other projects (while I enjoy the little of remaining summer).

When I looked at the boat in December, we confirmed the new fuel thank, then engine started easily and had a quick look over (I was not there when surveyor did this), but the transmission would not have been looked at. I really wanted to get a boat before end of year (deep freeze) so I could get working on it in spring.


-PC

[Craig Illman]

Re: Laser Tachometer mentioned above. I bought one of these and got to try it today. I thought I was a bit overpitched, but found that my panel tach is reading about ten percent low, so I'm pretty much in the ballpark on where I should be for top RPM under load. It was pretty inexpensive. Certainly worth it to me.

Thanks Rick!

Craig