305 chevy inboard no power rpm increase under load?

[jamesdad]

i have a 305 chevt volvo penta io that revs up fine in neutral but when you put it in forward/reverse it will just not go abovr 2250 rpm it just has no power its a 24.5 bayliner with a 5.0 chevy and vp penta out drive. it is fine in neutral!n please help! thanks in advance james

 

[achris]

Re: 305 chevy inboard no power rpm increase under load?

i have a 305 chevt volvo penta io that revs up fine in neutral but when you put it in forward/reverse it will just not go abovr 2250 rpm it just has no power its a 24.5 bayliner with a 5.0 chevy and vp penta out drive. it is fine in neutral!n please help! thanks in advance james

Dirty bottom?

 

[ENSIGN]

Re: 305 chevy inboard no power rpm increase under load?

Check your gas & filters

 

[Silvertip]

Re: 305 chevy inboard no power rpm increase under load?

New to you boat? The last tune-up was when? Compression is? Carb is fully opening? Fuel is how old? Did it run fine when last run? Was any recent engine work done by you? And just so you know, an engine running on half it's cylinders will rev in neutral because there is no load on it. Start with the basics.

 

[Bondo]

Re: 305 chevy inboard no power rpm increase under load?

Ayuh,...... Start Here...

List of possible causes of low WOT (Wide Open Throttle) rpm.

In no particular order

Engine Won't Reach Operating RPM. Check

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

Don S.

 

[180shabah]

Re: 305 chevy inboard no power rpm increase under load?

...and stop reving the crap out of it in neutral, it is destructive and provides ZERO useful information...

 

[DaNinja]

Re: 305 chevy inboard no power rpm increase under load?

Check your gas & filters

Yep. I spent a whole bunch of time last year troubleshooting a 5.7 with that same problem. It turned out that changing out the fuel filter/water separator fixed my problem. A fix that took all of five minutes with most of that time trying to find a filter wrench.