mid cabin - WOT

BobCT · Post by **BobCT** » Thu Jun 10, 2010 10:53 am

I know this topic has been beaten to death but I was just looking at the spreadsheet that RWS put together. Was the 3,600 shown at WOT?

When I bought the boat last year, the survey showed WOT around 3,800 - 3,900. I keep hearing that it should be more like 4,200-4,400.

Over the winter, I replaced virtually every consumable engine part (both sides)and rebuilt the carbs. The boat starts/runs great but I'm maxed out around 3,600 @ 20 knots on the GPS. It seems odd to me that both engines would be maxing out almost identically. I did verify that the throttles have full travel (they're new) but haven't checked the RPM's with my digital tach. I do have some old gas, possibly two years which I'm trying to burn off. Carbs have been adjusted with a vac gauge and timing is set correctly at idle, have not verified timing advance yet. Plugs, filters, wires, cap/rotor, coils, fuel pumps are all brand new.

Bottom is clean, props are untouched (will do that for next year) and are original Nibral 3 blade 16x17's.

Are you guys with the same setup getting up over 4,000?

Bob

RWS · Post by **RWS** » Thu Jun 10, 2010 12:39 pm

WOT SHOULD BE 4400.

While I did reach 4300 for a moment, I was afraid, VERY AFRAID of running those 2600 hour engines (well, one of them) at any kind of high RPM long enough to run th etest, therefore I stopped at the point where I became uncomfortable.

The port engine was factory original and had a great deal of valvetrain/timing gear/chain slop. I was always afraid of that engine skipping time and dreaded doing an in the boat repair on that.

Anyhow, you know the rest of THAT story!

RWS

S.A.M. · Post by **S.A.M.** » Thu Jun 10, 2010 12:41 pm

Bob,

I feel your pain. I posted 3 weeks back about the same problem. Supposedly our boats came with 17 dia x 16 pitch wheels. I have yet to find any printed information on performance numbers for the 10M Midcabin.

Mine has 17 x 17 and will top out a 4000 rpm and 25 mph. At 3000 rpm the boat is running @16.4 mph. I ordered and have received new 17 x 14 four blades. Three different prop companies ran their prop calculators and all came up with the same thing.

Unfortunately with the oil spill, which now is hitting us here in Pensacola, I don't know when I'll gett a chance to put them on and find out the results. But when I do, I'll email you.

BobCT · Post by **BobCT** » Thu Jun 10, 2010 3:28 pm

first, sorry to hear about the affect on your boating. I'm in LI sound and there have been many conversations along the lines of "what if that happened up here? The don't drill here but a lot of big tankers come in/out of New Haven harbor.

Let's stay in touch and see what changes you get. I know it can't be all props (since you're at least getting to 4,000) so I'll keep working on mine.

Bob

sluggo · Post by **sluggo** » Mon Jun 14, 2010 11:28 am

these are the numbers John at marine tech gave me,
Low cruise 2850 rpm =16 mph
mid cr 3300rpm =21 mph
high Cruise 3750rpm = 26 mph
max = 4400rpm = 33mph
that being said when I first got the boat in 2000 I remember hitting in the 42-4400 rpm range 1 time. Like others it made me nervous with length of time on the old engines.

Over time as I have put more junk on the boat then taking off, now when I try to max out it is in the 3800 3900 range, although I have not ever tried this year.

I run 16 x 17 3 blade cup, neighbrow (spelling is wrong). John says that is what the boat specs call for.
Just fyi, btw I twin 454 crusaders.

S.A.M. · Post by **S.A.M.** » Mon Jun 14, 2010 4:03 pm

Sluggo,

Your Express is lighter and balanced differently than our midcabins. The performance and handling in the two boats are very different.

So, unfortunately the speeds and rpms will not be same.

Danny Bailey · Post by **Danny Bailey** » Mon Jun 14, 2010 7:10 pm

Did you say two year old gas??? And you're puzzled that your engine won't reach full RPM?

gardnersf · Post by **gardnersf** » Tue Jun 15, 2010 12:03 am

Bob, I ran mime at WOT a couple fo weeks ago after replacig the distributor on STBD and cleaning the carb filter. I got 4300 on Port and 4100 on starboard, starboard started surging a bit but I accidentally twisted the fuel line a bit trying to get to the carb filter. It;s not leaking but would provide a small flow restriction.

I actually don't know what props I have. Gas was last years gas still

BobCT · Post by **BobCT** » Fri Jun 18, 2010 8:27 am

I'll probably be through all of the original gas this weekend, there's not much left now. It hasn't run any better/worse during the process.

The engines are running great... easy start, smooth idle and no dead spots during throttle up.

I'm willing to bet we both have the original Nibral 3 blade props. I never got around to getting them pulled and scanned or replaced. I'll see what Sherman comes up with on his boat once he gets them installed.

Bob

RWS · Post by **RWS** » Fri Jun 18, 2010 9:30 am

I bought my express from the original owner.

She came with 4 blade bronze, 3 blade nibral(spares) and a spare shaft.

After prop work with the 454's we ended up with the following:

4 blade bronze 18x19
3 blade Nibral 17x22

Keep in mind this applies to the Express dirveline layout and may apply to other aft cabin, sedan and convertible models with the engines forward - not the mid cabin

on another note, the stock 9x24 trim tabs were replaced with 12x24 tabs with 3" drop fins. This provided notable fuel economy improvement and GPS speed at any given RPM above displacement speeds and should apply to all of these boats regardless of layout.

RWS

sluggo · Post by **sluggo** » Mon Jun 21, 2010 1:37 pm

S.A.M. wrote:Sluggo,

Your Express is lighter and balanced differently than our midcabins. The performance and handling in the two boats are very different.

So, unfortunately the speeds and rpms will not be same.

duh!! They look the same to me!! (at least our avatar's do) I have (I think) a 10 meter express. What is the difference between the express and the mid cabin??

RWS · Post by **RWS** » Mon Jun 21, 2010 1:42 pm

follow this thread for the info re: differences

RWS

http://www.trojanboats.net/wforum/viewt ... 83dd04a2ab

sluggo · Post by **sluggo** » Mon Jun 21, 2010 1:57 pm

sluggo wrote:
S.A.M. wrote:Sluggo,

Your Express is lighter and balanced differently than our midcabins. The performance and handling in the two boats are very different.

So, unfortunately the speeds and rpms will not be same.
duh!! They look the same to me!! (at least our avatar's do) I have (I think) a 10 meter express. What is the difference between the express and the mid cabin??

I think I have a mid cabin, as I have an aft cabin, I have the 2 plexiglass 'port holes' on the deck, I have 2 port windows not 3, I have 2 metal full tanks, and a 'plastic' holding and water tanks, so I think I have a mid cabin.

RWS · Post by **RWS** » Mon Jun 21, 2010 2:05 pm

[/quote]

I think I have a mid cabin, as I have an aft cabin, I have the 2 plexiglass 'port holes' on the deck, I have 2 port windows not 3, I have 2 metal full tanks, and a 'plastic' holding and water tanks, so I think I have a mid cabin.[/quote]
=======================================

YESSIR, WE HAVE A WINNAH, COME ON DOWN, AND YES, SHE'S A MIDCABIN!!

RWS

Trojan Boat Forum

mid cabin - WOT

mid cabin - WOT

I recall that post but wasn't sure who it was.....

I have a 1987 10 meter express

ok, thanks