F 28 unable to plane.

MDrywa · Post by **MDrywa** » Mon Dec 31, 2007 2:23 pm

I have a 1976 F28 that I cannot get to plane. When I purchased the boat a few years ago it would go past 2800 RPMs. With an almost empty boat I could get around 16 knots but the motors were always straining like I was pushing a brick wall and she would not plane. At that time it had 14 X 10 props. I installed 13 X 9 props and I can get to about 3400 RPMs at 13 knots but I am burning 13 GPH per side and still not able to plane. At 2600 RPMs I can cruise at 8-10 knots burning 6-8 GPH per side.
It has twin 233 Mercs(351 Fords)with Rochester 2 barrel carbs. Velvet 1:1 V transmissions. 350 hours on one engine and 400 on the other. I have heard that these boats should cruise at 20 knots and max out at 28 knots. Some folks have suggested switching to 4 barrels. Does anyone agree that upgrading to 4 barrels would help or am I looking in the wrong direction? Any suggestions would be greatly appreciated.

raymond workman · Post by **raymond workman** » Mon Dec 31, 2007 2:48 pm

Does your boat have trim tabs on it to help it plain out faster

Stripermann2 · Post by **Stripermann2** » Mon Dec 31, 2007 2:56 pm

Is the bottom clean? A fouled bottom and running gear will knock you right down to nothing.

MDrywa · Post by **MDrywa** » Mon Dec 31, 2007 3:04 pm

The boat has tabs, in fact the previous owner added a plate to each tab to increase the overall size of the tab. I have tested the tabs several times and they extend and retract the full length. The bottom is clean, I have the same issue after launching in the spring with a fresh coat of bottom paint.

Thanks

prowlersfish · Post by **prowlersfish** » Tue Jan 01, 2008 11:29 am

Something is very wrong with your boat and or engines. you should have no proplem geting to the mid 20s and turning 3800-4200 rpm . are both engines having troulble turning up to right rpm ? I would think you would have no proplem turning the 14X10 props .

rossjo · Post by **rossjo** » Tue Jan 01, 2008 12:55 pm

Clean bottom was most likely, but now it sounds like your engines are getting tired ... check engine timing, plugs, etc., and go back to at least a 14x10 - you should be able to turn a 14x12 or more if its running right ... What RPM do you get on each engine at WOT?

If timing & plugs look good, comrpession check would be a relatively easy step (watch for sparks!). Plug wires are easy to replace as well - they don't last long in a marine environment.

LandVF36 · Post by **LandVF36** » Tue Jan 01, 2008 2:16 pm

I had the same issue a few years ago with a Chris Craft 283 with twin GM 283 V8s (rated at 185 hp ea when new) pushing 1:1 velvet drives and about 9100 lbs dry weight (I think similar to your Trojan). After replacing plugs, wires, cap, rotor I decided it must be the carbs. I spent some good $s on having the carbs rebuilt, bigger trim tabs. Check the compression, perfect. Then one day while on a short cruise at 8MPH, I rembered the last part of the ignition system, the coils! Replace both, and tada! On 14 x 10 wheels, I could suddenly run 19-22 MPH at 3800 RPM depending on how much fuel / beer / friends were on boat.

Don't forget to replace the coils... I guess mine allowed enough spark to run, but not enough when under a load to fully ignite the gas.

jordan · Post by **jordan** » Tue Jan 01, 2008 9:46 pm

LandVF36,
Where in Minnesota do you have your boat? I'm in southern MN but keep our boat in the Apostle Islands, WI.
Jim

LandVF36 · Post by **LandVF36** » Tue Jan 01, 2008 11:27 pm

We keep the boat on the Mississippi at Red Wing. We live in Prior Lake. We have a smaller trailered boat that we take up to Bayfield once a year, normally late July / Early August.
Mitch

MDrywa · Post by **MDrywa** » Mon Jan 07, 2008 6:45 pm

Thanks everyone for the advice. I definitely have a few things to check come springtime.

Trojan Boat Forum

F 28 unable to plane.

F 28 unable to plane.

humm

Where in Minnesota are you?