Join the C34 Association Today!
[C34 Home] [C34Tech Notes] [C34 Tech Wiki] [Join!]
Please login or register.
Advanced search  

News:

Pages: 1 [2] 3   Go Down

Author Topic: WOT too low. Speed down significantly  (Read 640 times)

0 Members and 1 Guest are viewing this topic.

Noah

  • Administrator
  • Forum - Master Chief Petty Officer
  • *******
  • Karma: 19
  • Posts: 1730
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #15 on: August 10, 2020, 02:48:11 PM »

I'm definitely hoping it is a filter or pump issue....That exhaust manifold is almost $1,400.00.
What part are you referring to? The exhaust riser for the M25 series engines is about $275 plus cost of the thermal wrap.
Logged
1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig

Stu Jackson

  • C34IA - Secretary
  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 70
  • Posts: 7675
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #16 on: August 10, 2020, 03:07:20 PM »

I'm definitely hoping it is a filter or pump issue....That exhaust manifold is almost $1,400.00.

John, as Noah said, you don't need an exhaust manifold, you need an exhaust riser.  Two different things.  The manifold is the big rectangular piece that you pour antifreeze into.

I wrote a Tech Note about replacing the riser, along with the muffler. 

Feb 2016:  https://c34.org/muffler-exhaust-riser-replacement-2015/
Logged
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Breakin Away

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 4
  • Posts: 426
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #17 on: August 10, 2020, 03:48:42 PM »

Hi John, glad you've got the boat, but sorry you're having an issue.

Don't assume that it's not growth. I was furloughed May-June and used the boat 3-4 days a week until June 26. The bottom looked the cleanest it has ever been at that point of the season. Then I went back to work (and the crap weekend weather), so the boat sat 5 weeks until August 1. During that time, I spun the prop in the slip once a week hoping to slough off any barnacle larvae before they could mature. Despite that, we took it out Aug 1 just to test the motor, and it had a hint of vibration at 2400, and >2500 was crazy bad (like would probably destroy my stuffing box). I hired a diver who cleaned the prop Saturday and took the boat out, and it ran fine all the way up to 3100 RPM. He said that this has been a very bad year for hard growth due to high temps and salinity. As evidence of this, you can see the sea nettles coming further north than it has in several years.

I know your symptoms are a little different than mine, but I'd say there's a good chance your prop is fouled. Hire the diver and then see how it runs.
Logged

2001 MkII Breakin' Away, #1535, TR/WK, M35BC, Mantus 35# (at Rock Hall Landing Marina)

KWKloeber

  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 32
  • Posts: 3647
  • "Positive Impact" 1984 C-30 #3573 trbsfk M-25
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #18 on: August 10, 2020, 04:11:21 PM »


What part are you referring to? The exhaust riser for the M25 series engines is about $275 plus cost of the thermal wrap.


Remember also the water-cooled riser option....
https://c34.org/wiki/index.php?title=C34_Exhaust_with_Water_Cooled_Riser

That some said couldn't be done (-sorry couldn't resist.)
Logged
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Oldlaxer1

  • Forum - Seaman
  • **
  • Karma: 0
  • Posts: 26
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #19 on: August 11, 2020, 03:30:43 AM »

Thanks everyone.  Filters arrive tomorrow so that will be the first thing I do. I need to get on a schedule anyway so it is not a bad thing even if it is growth. Not looking forward to changing the engine filter but I'll get it done.  I went down to the boat to make sure the fuel pump was "clicking" and it was as soon as the key was on.  I purchased a pressure gauge along with the filters for the Racor so I can monitor fuel pressure.  I had one on my last boat and it was helpful. 
We're scheduled for a 5 day cruise over Labor Day weekend so I'll probably schedule the diver a week prior to that.
Exhaust riser, not manifold, got it. Thanks...
Logged
John Novotny
1987 C34 #298

Jim Hardesty

  • Forum - Master Chief Petty Officer
  • *******
  • Karma: 10
  • Posts: 1173
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #20 on: August 11, 2020, 04:06:00 AM »

Quote
Filters arrive tomorrow so that will be the first thing I do. I need to get on a schedule anyway so it is not a bad thing even if it is growth.

I hope the filter change goes well and totally fixes the problem.  "But" if you have dirty fuel they may need changed again after only a short time running.  I always carry several new filters.  I suggest you spend a little extra time when changing  the filters to cut a plastic bottle or something to fit under the filters to catch any leaks, also at least one roll of paper towels.

Hope you have a good trip,
Jim
« Last Edit: August 11, 2020, 04:19:43 AM by Jim Hardesty »
Logged
Jim Hardesty
2001 MKII hull #1570 M35BC  "Shamrock"
sailing Lake Erie
from Commodore Perry Yacht Club
Erie, PA

glennd3

  • Forum - Petty Officer 2nd Class
  • ****
  • Karma: 3
  • Posts: 175
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #21 on: August 11, 2020, 05:05:31 PM »

Where are you on the bay?
Logged
Glenn Davis
Knot Yet
1990 Catalina 34 Mk 1.5
Hull 1053
TR/WK
M25XP
Patapsco River
Chesapeake Bay Maryland

Oldlaxer1

  • Forum - Seaman
  • **
  • Karma: 0
  • Posts: 26
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #22 on: August 12, 2020, 04:12:22 AM »

We keep the boat at the Anchorage Marina in Baltimore. 
Logged
John Novotny
1987 C34 #298

Oldlaxer1

  • Forum - Seaman
  • **
  • Karma: 0
  • Posts: 26
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #23 on: September 05, 2020, 04:54:09 AM »

Just an update.....it was growth on the bottom and prop. RPMís and speed are back where they belong. I will be checking prop pitch when I haul her. Iím thinking with an adjustment I can improve speed a bit without lugging the engine.  Happy Labor Day weekend for all us laborers out there😎
Logged
John Novotny
1987 C34 #298

Ron Hill

  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 55
  • Posts: 7089
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #24 on: September 05, 2020, 01:48:28 PM »

John : If the boat has been doing a lot of sitting for the past 6 weeks you always need to have a diver check the prop. 
If you dive under and look at it the prop the blades will look like "Boxing Gloves"!!! 

A thought
« Last Edit: September 05, 2020, 01:49:50 PM by Ron Hill »
Logged
Ron, Apache #788

scgunner

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 5
  • Posts: 417
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #25 on: September 06, 2020, 08:39:16 AM »

Not sure what your growth rate is like in Baltimore but here in SoCal we get the bottoms done every four weeks and by the end of the fourth week that bottom is looking pretty grungy, especially in the summer.
Logged
Kevin Quistberg                                                 Top Gun 1987 Mk 1 Hull #273

Ron Hill

  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 55
  • Posts: 7089
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #26 on: September 06, 2020, 02:24:30 PM »

John : Don't know what kind or brand of bottom paint you are using, but bottom paint usually does a pretty good job with keeping the barnacles off the painted surfaces.  You might get some slime while sitting awhile.
 
The running gear like the prop is a different matter! It's a constant battle to keep the "nasties" off the prop - many, many post on that topic!!

A few thoughts

Logged
Ron, Apache #788

Breakin Away

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 4
  • Posts: 426
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #27 on: September 06, 2020, 08:13:51 PM »

Hi John,

I'm glad the diver cleared things up for you. Looks like my initial hunch was correct.

This is the first year I've had to hire a diver to address vibration due to hard growth on the prop - my prior four years with the boat, everything worked fine throughout the season, and at haulout there would be 5-6 barnacles on the prop, always in innocuous places (i.e., near the hub but not the outer parts of the blades). Last year there was an extreme number of barnacles on the brand new strut that I noticed after haulout.

For the past 5 years I have used Pettit Prop Coat Barnacle Barrier on all running gear. It has helped when compared to untreated surfaces, but it's far from perfect. One guy on Sailnet (who has now been banned) repeatedly swears by Prop Speed (2-part epoxy? paint followed by clear coat, I think), but it's way too overpriced for my tastes, and this same guy still has to hire a diver a couple times a year. If I were paying $300 for prop paint, I'd be very disappointed if I still had to hire divers. Also, I'm concerned that any 2-part curing paint like Prop Speed would be very difficult to remove down to bare metal once it needs replacing. The guy who runs the nearby prop shop in NJ told me that he'd only recommend spending the money on Prop Speed for huge powerboats with huge props. He sells the $28 Pettit stuff for 95% of his customers.

There is now a lower cost competitor for Prop Speed called Prop Glide. However, it's still pricey (close to $200 IIRC) and, I suspect, difficult to remove.

This year I applied the Pettit stuff again, but overcoated it with some copper-free Pettit Hydrocoat Eco that I picked up on clearance from Defender. I won't know how it worked until haulout, and it won't really be a legitimate comparison vs. prior years because I hired a diver for the first time this year.

My comments here are relevant to my area in the mid-upper Chesapeake (Rock Hall). I know that you're right across the Bay in the Patapsco, which is generally similar, though probably even more nutrient-rich.
Logged

2001 MkII Breakin' Away, #1535, TR/WK, M35BC, Mantus 35# (at Rock Hall Landing Marina)

scgunner

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 5
  • Posts: 417
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #28 on: September 07, 2020, 07:04:20 AM »

A guy got banned for recommending a prop paint?
Logged
Kevin Quistberg                                                 Top Gun 1987 Mk 1 Hull #273

Breakin Away

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 4
  • Posts: 426
    • View Profile
Re: WOT too low. Speed down significantly
« Reply #29 on: September 07, 2020, 07:07:50 AM »

A guy got banned for recommending a prop paint?
I donít think so. Iím not sure why he was banned. But he is unavailable for answering any questions that John may have, which is why I mentioned it.
« Last Edit: September 07, 2020, 10:56:20 AM by Breakin Away »
Logged

2001 MkII Breakin' Away, #1535, TR/WK, M35BC, Mantus 35# (at Rock Hall Landing Marina)
Pages: 1 [2] 3   Go Up