Volvo Penta 140 will not WOT

[john lyons]

I have a 1979 Glas Ply boat with a Volvo Penta140A that I cannot get to
consistently rev above 3500 rpm.
I have done the following:
changed the plugs and plug wires, put on a new distributor cap, checked the
timing, checked the coil by seeing if it gets hot when running the motor (it
does'nt, put an in line fuel filter, the points looked good, checked the gas tank vent line to see if it was plugged (it was not) ran the boat with the
gas tank filler cap open, and had the carburetors rebuilt by a shop.
The boat sometimes will rev up to 5200 rpm and run fine but most of the
time it will only rev 3500 to 3800. Sometimes it misses other times it runs
smoothly but will not rev beyond 3500. The boat temp normally around 190.
Does anyone have experience or advice concerning about this problem?
Thanks for any help.
Montana Boater

 

[captmello]

Re: Volvo Penta 140 will not WOT

Could be any number of things. I guess I would begin by doing a compression test on the engine to make sure its healthy.

I would also tune up the distributer, points, condenser, wires. With the old boats you need to be up to date on your tune up parts. I would also make sure to adjust the dwell with a meter and reset the timing. I would also check to make sure the timing is advancing propertly.

Montana..., are you at a high elevation?

 

[Eric 3.7LX Alpha 1]

Re: Volvo Penta 140 will not WOT

Here is a list from the "Adults Only" sticky at the top of the forum:
List of possible causes of low WOT (Wide Open Throttle) rpm.

http://forums.iboats.com/showthread.php?t=295070

 

[john lyons]

Re: Volvo Penta 140 will not WOT

Thanks for the quick reply! I had the shop go through everthing when I bought
the boat. The compression and everything checked out OK when it was in the
tank. I will take your advice and replace the coil. I was thinking about getting rid of the points and getiing new point less system.
I live in Billings which is at 3124 ft.
Thanks again
Montana Boater

 

[captmello]

Re: Volvo Penta 140 will not WOT

I didn't say coil.

Pointless systems are fine but it may not solve your issue.

The timing may not be advancing correctly, sticking. When you do your distributer work, check the springs and weights for corrosion.

On the other hand you may have water in your fuel. Do you have a fuel/water separator filter?

 

[john lyons]

Re: Volvo Penta 140 will not WOT

I don't know if I have a fuel water separator, where is it located?

 

[Don S]

Re: Volvo Penta 140 will not WOT

I don't know if I have a fuel water separator, where is it located?

They didn't come with water seperating fuel filters back then. They didn't even exist back then.

Here is a list of possible causes of low WOT (Wide Open Throttle) rpm. Follow it, and you will find the problem.

Not listed in any 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.

 

[john lyons]

Re: Volvo Penta 140 will not WOT

Thanks for the info. Here we go!