1971 Fiberform w/ OMC 327 V8

[toolisfna]

I just aquired a 21 foot Fiberform boat for a extremely low price but the problem is that it doesnt accel in the water. I am new to boats and dont know much about the technicalities of them but I am curious if anybody would know why the prop and engine runs good when outside the water but when I drop it inside I am only hitting 1500 RPMs with the motor and only going 5-7 miles per hour. The carb also backfires and all in all it runs horribly. Any information would be greatly appreciated.

 

[Don S]

Re: 1971 Fiberform w/ OMC 327 V8

Since you just bought the boat, EVERYTHING on this list is a possibility.

Engine Won't Reach Operating RPM. Check

• Fuel condition. Type and Octane possibly old fuel
• Propeller pitch or diameter, damaged blades
• Restricted fuel pickup tube or anti siphon valve Fuel System Test
• Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
• Marine growth on hull and outdrive
• Wrong gear ratio in outdrive
• Restricted carburetor air intake (clogged flame arrestor)
• Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
• Poor cylinder compression Compression Test
• Carburetor defective, or wrong type.
• Fuel pump pressure and vacuum
• Boat overloaded, improperly loaded, or improperly trimmed.
• Engine Overheating
• Engine timing and ignition system operation (Full tuneup done recently)
• Remote control cables and linkage for proper travel to open throttle plates fully.

 

[toolisfna]

Re: 1971 Fiberform w/ OMC 327 V8

I Appreciate The Ideas. If It Would Be Any More Help The Previous Owner Had Left Water In The Engine And It Cracked On Of The Heads. He Had The Boat In The Shop And Had Both Heads Replaced. I Beleive He Said It Ran Like That After The Heads Were Replaced. The Motor And The Boat Is In Very Clean Condition. I Am Just Hoping That It Is A Motor Problem Versus The Propeller. Like I Said It Runs Awesome When Testing It With Water Hooked Up But Runs Horrible When Running It In The Resevior.

 

[bomar76]

Re: 1971 Fiberform w/ OMC 327 V8

Pretty easy for an egine so sound great on muffs when there is Zero load on it, it the water where there is actual resistance is a whole 'nother matter.

Go thru the checklist Don posted, doesn't matter how clean the thing is, or what you hope (and I never ever heard of anybody HOPING for an engine problem instead of a prop issue).

BTW, loose the Capitalizing Every Word Syndrome, makes your posts hard as hell to read.

 

[whywhyzed]

Re: 1971 Fiberform w/ OMC 327 V8

OMC never used a 327 - you probably have a 307, so god only knows what parts were put into your 307 if the previous owner went around town telling everyone it was a 327. Could be wrong heads.
Mercruiser oddly used a 327 one year (1977-250HP), but not OMC

 

[whywhyzed]

Re: 1971 Fiberform w/ OMC 327 V8

I Am Just Hoping That It Is A Motor Problem Versus The Propeller.

???
O...K....
I think you'll get your wish