Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

[scooper77515]

Just got the boat, runs like a dream. Clean, low hours, good maintenance. Glastron GX185, VolvoPenta 4.3 190 hp. 185 hours. 150 from the last year alone, sat much of the previous 6 years.

Hops out of the hole in less than a couple seconds, and gets to 3500 rpms in seconds. Then stops there. Around 40 mph.

Actually, plenty fast for us, but I read that it is supposed to go to 4500-4800 rpms, somewhere into the low 50s mph.

New dist cap, rotor, plugs, wires, didn't help. Old ones were shot, though. Idles smoother now, and accellerates more quickly, but still stops at 3500.

Swapped prop from 24 pitch to 21. Previous owner hit something and put a little dent in old one (taking it for straightening for a spare).

Carb is opening up all the way at full throttle.

I doubt fuel filter/water separator has ever been changed, and no carb clean/rebuild.

What are common sources for the engine stopping its pull a thousand rpms early?

 

[Don S]

Re: Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

Would have helped to know what year and type of drive you have.

Here is a 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.

 

[scooper77515]

Re: Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

I thought I put that info in my signature. Back to User CP to clarify.

EDIT--Nope. Signature is not showing up...

 

[Don S]

Re: Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

I thought I put that info in my signature. Back to User CP to clarify.

EDIT--Nope. Signature is not showing up...

Interresting
Your signature doesn't show up here, but it did show up in the PM you sent me.

2003 Glastron GX 185, with VolvoPenta 4.3GL, 21 pitch prop.

 

[scooper77515]

Re: Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

Yup, I cannot see it on my posts either. Put the sig and pic on there, but it won't show

 

[scooper77515]

Re: Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

Ok, now it is showing on this most recent post, but no pic.

Totally confused.

Maybe after a couple more posts, the pic will show up...

 

[Don S]

Re: Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

Might try putting your picture back in. I deleted it and removed your signature line after removing the picture didn't work.
Then when I put your signature line back, it didn't even show up at first either. Now it is.

I don't have a clue ...................

 

[scooper77515]

Re: Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

As long as sig is in there, pic isn't of any priority.

 

[scooper77515]

Re: Probably a common question. RPMs max out at 3500. 18.5' VolvoPenta 4.3.

Add to #1 on your list...

#1--verify Tachometer switch on back of unit is set for appropriate number of cylinders

It was set for 8 cylinders, I have a V6. That puts me right at 4800 rpms, where the boat is SUPPOSED to max out.