1977 26' Trojan Flybridge suffers from 9 knots

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Sivak
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Joined: Tue Aug 23, 2005 7:14 am

1977 26' Trojan Flybridge suffers from 9 knots

Post by Sivak »

I purchased this boat Sept last year. I did not have a chance to get out too many times before the WI weather dry docked me. My first time out this spring I ran about 16 knots (GPS) as I ran over to the marina. I was ecstatic! She planed and handled great, wake flattened, all was good. Since then I can't seem to get her to plane out fully, my RPM's hit 3200 and I get about 8.9 knots on GPS. I have 351 Cleveland with about 500 hours on a rebuild. The prop is 9 pitch cupped, either a 13 " or 14" dia. I am drawing a blank at the moment.

She fishes Lake Michigan great! I just would feel more comfortable running 3200 knowing I'm cruising versus 3200 running full bore. The engine seems fine - not over worked - and feels like she has more to give.

Any help, advice would be greatly appreciated!!

Todd Sivak
26' Trojan Fly
chucka
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Post by chucka »

Issues that affect performance include: compression, carburation, timing, prop size, cup & condition and the condition of the botttom.

I spent most of this summer tweaking and tuning trying to get more performance out of a remanufactured 240 hp Chrysler lm318 I installed in my 1975 Trojan F-26 this spring. The carb was rebuilt by http://www.carburetorUSA.com in NJ, which solved my problem. Previously I was only able to get 3500 rpm and a disappointing top speed of 14-15 knots. Prior to the carb rebuild, she seemed to be straining at all speeds.

I was able to hit 4000 rpm this week with the rebuilt carb with a top speed of 18.2 knots [two runs in opposite directions ranged from 18.0 to 18.4]. I can cruise economically before the secondaries kick in at about 13 knots, which is where the boat feels comfortable. She is up on a plane at that speed with the wake flattened out. That may not sound like a speed demon, but I'm satisfied with it. This boat isn't really built for speed. I extended the keel and replaced the rudder with a larger one to improve tracking stability and maneuverability. I had expected increased drag from these changes to have some impact, but was convinced that the engine wasn't running up to snuff.

My biggest mistake was transferring the carb, intake manifold & distributor from the old engine to the replacement without doing anything to check them out or fix issues that I was not aware of.

If you are interested in the history, look at Chrysler threads in the forum on http://www.marineengine.com/discus/mess ... 1124648871 beginning in July to see how I learned about replacing the advance springs in the distributor, which I was able to get done locally for a very reasonable price. Fixing the distributor got me from about 2800 RPM to 3500, and solved a back firing issue. It took the carb rebuild to get the rest.

CarburetorUSA told me that the carb had been rebuilt previously and the choke linkage was not assembled correctly. Straightened that out, cleaning out the carb and adjusting things did the trick.

I'm still running my 14 dia. x 10 pitch prop with no cup. (reconditioned this spring) I had gotten input from another Trojan F26 owner, indicating that performance on the F-26 is very sensitive to putting a slight cup in the prop. I didn't find this to be necessary.

summarizing for future reference:
1975 Trojan F-26, factory remanufactured LM318, FWC, 14 dia x 10 pitch prop no cup, velvet drive 1:1 straight drive. Rudder increased in size from 12" h x 5" L with 1" dia shaft to 17" h x 12" L with 1.25" dia shaft. Keel extended ~6 inches from original lines.

Here is what I measured. This is the average of two runs in opposite directions.
rpm knots
2,600 10.9
2,800 12.3
3,000 13.4
3,200 14.5
3,600 16.1
4,000 18.2

This Speed and power data is not a precise science. These measurements are very sensitive to loading the boat. One person on board and half a tank of fuel yields better performance than full tanks and the whole family on board.

If you search this forum and marineengine.com, you will find a lot of information from other Trojan owners with similar performance experience.

Regards,
Chuck
formerly
Lots A Luck
Trojan F-26 Express
Narragansett Bay, RI
Sivak
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Post by Sivak »

Chuck,

I spoke to a gentleman in Jersey who read the speed specs to me for the 351 Cleveland & Chrysler 318 for a '77 F-26. According to "Bob", here are the speed specs for each:

Engine RPM speed
351 3,000 21 mph
351 4,000 32 mph
318 3,000 23 mph
318 4,000 30 mph

This assumes a 14" X 10 pitch super cup prop.

I don't know what book he got this from but I sure as heck am going to try to get as close as I can to these speeds! You may not want to settle for 18 knots. In addition to compression, I am also investigating the posibility of a slipping transmission as a cause for lack of speed.

The 351 will burn 10.5 GPH at 3,000.

Todd
chucka
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Post by chucka »

I'm not sure where the gentleman from NJ got those numbers either, but he might have been a little dizzy from the recent spike in gas prices. Here is a clipping of the F26 review from Power Boat Guide published in 1999.
Image

Paraphrasing....A good running boat with a single 230 hp inboard will reach a top speed around 25 mph.

I thought I read somewhere that the manufacturer's published top speed was usually measured with one person on board, nearly empty fuel and water tanks and going downhill.

Good luck with yours! Send some photos when you get a chance. I took some running photos last weekend and will post some soon.
formerly
Lots A Luck
Trojan F-26 Express
Narragansett Bay, RI
Sivak
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Post by Sivak »

Chuck,

I can't tell you how much I appreciate your willingness to communicate. Your inserted piece was perfect - thanks. I have the 26 flybridge. Nonetheless, I would take 20 knots over 9 any day of the week! I just hope that I get some answers this weekend as I work on the engine!

I attempted to add pictures but was unsuccessful. I will try again another time.

Todd
[/img]
frank v.
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Post by frank v. »

Hello,im new here.

Also have a trojan boat who is 27 feet,but now when i look at the picture on this site i begin thinking i also have 26 ekspress...

I have 180 hp diesel whith volvo penta 290 dp.cruising speed 23 knots full speed 28 knot

Image

frank v.
norway
fvj@dean.no
Sivak
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Post by Sivak »

Frank,

Hello! Thanks for taking the time to write & provide information. Your Trojan certainly looks a lot like the 26' express. You sure seem to have a good bit of speed too!

This winter I will have my trim tabs repaired to see how much of a difference they make. I also will swap my 14 X 9 cupped prop for a 14 X 11 cupped prop (they call for a 14 X 10 super cup) and see what the total difference is. Until then ...

Todd
frank v.
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Post by frank v. »

Trim tabs are a very good thing,make a big different,the boat is running a lot easyer whith that..
Goes very fine dawn to 10-11 knots.
I have build on a new targa on this boat,and made a new swimming platform.
I think my boat is the only one here in norway,have not seen some other..

Image

Image

frank v.
JimG
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Location: Dickinson, TEXAS!

Post by JimG »

Sorry, "newbie dragging up an old thread" alert!

My '79 F-26 Flybridge (318 Chrysler, 1150 hours and 14x9 cupped prop) makes 22mph at 3500 rpm with a clean bottom. If I empty the boat and take the bimini down I can go a few miles faster at 4k rpm. But weight and bottom condition really drag me down. I usually cruise at 16-17mph at 26-2800rpm getting around 2 mpg (Navman gps flowmeter).

Jim
1970 Donzi 18 2+3, 1993 Stryker 3800 Thunder
Sivak
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Post by Sivak »

Jim,

I appreciate the note. Since I first posted I have sand blasted the entire bottom (with walnut shell media) and found a significant amount of osmotic blistering. We figure there has been a good amount of water absorption decreasing speed (and the paint was several layers thick & uneven). I have removed the swim platform and am in the process of removing the flybridge (which I am struggling with internally). Once she dries out this spring we will patch and sand the blisters, give her a water barrier (4 coats of Interlux 2000e) then a smooth coat of paint. The trim tab hydraulics are cracked & leaking. I found a decent pair of new actuators. I do not know what to do about the prop. I have both a 14X11 with very little cup & a 14X9 cupped set of props and don't know which would be the best to start with. One gentleman is heavily suggesting that I take the 14X9 down to an 8. I have not been able to find what prop the boat was originally designed & rated for. I guess if I can at least get past the 9 - 11 knots range it is an improvement - hitting 20 knots would be pure joy!

Any help, thoughts or suggestions are ALWAYS appreciated!

Sincerely,

Todd
JimG
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Post by JimG »

Sivak, in my experience these boats are extremely sensitive to bottom condition and weight. I attribute it to the 1:1 transmission providing no torque multiplication. (And the low hp motors) Other inboards I've driven with 2:1 or 2.5:1 trannies are much less sensitive to weight and drag. (I can vary my rpm 200 or more just by shifting weight around...)

I had a bottom job performed on my boat shortly after purchasing it. Six months later I could barely plane. I thought I had an engine problem. Had the bottom cleaned by a diver, and got all my speed back! Now I have the bottom cleaned quarterly.

My boat has a 14x9 cupped prop. It seems about right for these boats.

Just my 2 cents: Keep the flybridge. I love driving from there, especially at night...

Jim
1970 Donzi 18 2+3, 1993 Stryker 3800 Thunder
Sivak
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Post by Sivak »

Jim,

Boy you are right on! I am guessing that the new smooth, baby's @ss bottom will be about 75% of the issue. With the moisture absorption & lack of ability to plane out properly all fixed, I am guessing that the added weight of the fly will not make any difference. I will keep the flybridge for now (I will most likely just remove the ladder & see if I can find a folding ladder somewhere). My kids (7 & 5) will probably freak on me if they can't get up there in the future to drive.

I am torn about the prop still. I have a tolling motor for fishing so if I go with the 14X11 I may get a few mph's but risk bogging down the engine. I would lose the ability to troll with the big motor too. With the 14X9 on your boat, what is your slowest idle speed?? 2mph? 2.5? I need to be able to get down to 1.8 or 2 mph.

Anywho, I appreciate the perspective!

p.s. where are you located that you clean the bottom quarterly?? FL? CA? We are up in the frozen tundra of Wisconsin ... Milwaukee


Todd
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Paul
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Paul

Post by Paul »

Todd,

If you have a trolling motor, I would recomend using only that motor for trolling. When trolling with your main engine, this low RPM does not allow your 1:1 transmission to build enough hydraulic pressure to keep the clutches fully locked up. This slippage may not be noticable while trolling but will lead to premature transmission failure due to worn clutch plates.

Hope This Helps
Paul
Cruise Control
'78 F-26
JimG
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Post by JimG »

At slowest idle, I'm around 2-3mph. That's 550-600rpm, just barely ticking over. With the 1:1 ratio, don't know if you can go lower without killing the engine. In a good state of tune, that 351W will idle quite low. My 351W in my 1970 Donzi will idle around 500rpm all day long.

I'm in Clear Lake, near Galveston, Tx. Pretty mild winters here, almost never freezes. We boat year 'round here. In fact, I'll be heading out tomorrow... temps in the 70's expected. :lol:

Jim
1970 Donzi 18 2+3, 1993 Stryker 3800 Thunder
Sivak
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Post by Sivak »

Jim,

Thanks for the information. There were days were I could idle all day and run about 2.3 mph on GPS and others where she'd quit and stall every 10 to 20 minutes. We will see what spring brings.

They are calling for low to mid 40's here for the next week. Wish I knew the freeze was over!!

Todd
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