honda 50hp four stroke cant go full throttle

[stingrayzp]

hi just put a honda 50hp on my 24ft pontoon boat its a 1999 has 172 hours on it runs great but when i give it full throttle sounds like a dead miss or to much fuel falls on its face its only turning 4600 rpms ne one have any ideas runs fine at 3/4 throttle it turns 4200 at 3/4 thanks mike

 

[cp]

Re: honda 50hp four stroke cant go full throttle

Try a lower pitch prop.

 

[Marv]

Re: honda 50hp four stroke cant go full throttle

Running too high of a pitch prop, loads up with fuel at WOT running too low of RPM's.

 

[Jellyfish12]

Re: honda 50hp four stroke cant go full throttle

has it ever ran good at full throttle? if so try having someone squeeze the primer bulb hard a few times and see if it smooths out. I have this problem and not sure what the problem is. if it ran good before than it is probably not the prop.

 

[abornpatriot]

Re: honda 50hp four stroke cant go full throttle

I Have The Same Problem.......i Cleaned Carbs(3) 4x's Changed Out Water/gas Filter 2x And The Small Gas Filter 1x. Tuned Carbs About 50x's. ......... She Purssssssss In Neutral But Under Load She Quits. I Hate Quitters. I Am Ordering A New Main Hose From 6gal. Tank To Engine. I Have No Other Ideas. Oh Ya I Also Dumped About $20 Dollars Of Gas In Gas Stations Tank. Than Filled W/ New Gas............same Result
Can The Timing Belt Be Stretched? If Sooo She Would Start Hard Right?( She Always Starts Right Up) Any Help And I Would Be Greatful.
Abornpatriot

 

[1730V]

Re: honda 50hp four stroke cant go full throttle

50 ponies on a 24' pontoon is one heck of a load. Your prop pitch is critical. Probably something in the 10-11" pitch range will get you in the ball park.

 

[Skinnywater]

Re: honda 50hp four stroke cant go full throttle

Not very likely prop pitch will cure a misfire.

I had #2 sparkplug burnout inside the insulator @ around 200 hours with my BF50. It idled great but would fall on it's face at higher RPM.
If I remember the plugs are supposed to be changed @200 hours even though they look good.

Remember also your motor has a protection feature that will cut power appox. 1/3 if it is overheating or experiencing oil pressure problems.

 

[Frank Martin]

Re: honda 50hp four stroke cant go full throttle

Prop Should Be A 4 Blade 9 Pitch Prop On That Boat
A Set Of Vacume Gauges Will Tell You If You Have Carbs Acting Up
You Can Try Pulling One Plug Wire At A Time To See If The All Make The Same Difference If You Dont Have The Gauges (make Sure If You Pull Wires Off While Running You A Well Insulated Pair Of Pliars) We Use A Set Of Industrial Fuse Pullers In The Shop . If Carbs Are The Problem The Gauges Will Be Needed For The Final Adjustments After Cleaning / Rebuilding