F26 top speed problem

[lure washer]

I own a 1977 F26 cruiser with a 318 Chrysler. Manual states that engine should achieve 225 HP at 4000 RPM. I can only get it up to 2800 RPM under load. The boat has a 14", 9 pitch prop. Is this the correct prop for this boat ? Have been told by one supplier to change to a 14" 13 pitch prop. Also engine is not governed at 2800 RPM as in neutral it revs up fine. Thanks, any help will be appreciated.

[prowlersfish]

If your only turning 2800 now changing to a larger pitch will make it worse . Your currant prop is what a lot of F26s are running . Now some questions so you can get better info . What speeds are you getting at 2800 ? Is the 4 barrel opening fully ? If the boat bottom and running gear clean clean clean . Has it ever turn more then 2800 ? If so what changes have been made since then . And has the tach been checked ?

[lure washer]

Thanks for responding, Top speed is approx. 14-16 MPH depending on conditions. I am in the process of sanding the bottom of the boat, it was fairly rough to the feel. Had the carb checked by a mechanic, all he found wrong was the chock was not coming fully off. I looked into this while winterizing the engine and found that someone had put oil in the little reservoir where the choke spring is. Cleaned it o out, hopefully that will help. I have not had the tach checked but it has been suggested. I just bought the boat this past summer so it has never reached full RPM while I have owned it.

[vabeach1234]

May want to check the timing. Make sure it's advancing like it should.

Also make sure your trim tabs are working.

[gitchisum]

+1 for checking the tabs.

My f26 ( 77 fb model with 233 MC and 1:1) was sensitive to weight distribution and 100-200 rpms could be gained by getting a few passengers up front in the cabin. I had a problem with my tabs leaking and had to run in without them, 11 mph was all I could muster at 3500 rpms.
I was turning a 14x9 cupped prop and topped out about 3800 and 21 mph. One issue I know existed was I had one weaker cylinder ( 110) and the rest about 125. You may want to check your compression along with what everyone else is suggesting.( I was on first rebuild with ~4000 hrs on block, was getting close to next one)

Bottom condition, tabs, and engine performance ( timing, compression, fuel, air ) are your biggest factors. Others may be : (Tranny?) ( Cables? )

Good luck

[larryeddington]

I hope to hear a solution, I have been fighting the same issue with my twin 318 f28 and have no for sure fix yet.

[prowlersfish]

There can be many causes of low rpm . What may fix one boat could be irrelevant on the next .

[larryeddington]

I have a set of 14x9 and have not tried it yet, true his is single engine and mine dual so Paul you could be correct. I hope he gets it figured out.