Volvo 501b - still bogging

[jimbresee]

Hey there....
I'm still struggling with a volvo 501b that won't accellerate well, and can't get to full RPM.

Since the last time I asked...

My mechanic pulled the holley carb and replaced it with a new Edelbrock 1409 600cfm carb.

The boat is running even worse, and can't get up on a plane.

Here's what we've treid so far:

1. New fuel pump
2. Tested fueling from seperate can (to isoloate inboard feul pick as the source of the problem).
3. New plugs
4. New plug wires
5. Cap/Rotor
6. Checked Timing and max advance
7. New Fuel Filter
8. New Coil
9. Isolated engine from boat wiring by wiring from battery to coil.
10. Tried a 'loaner distributer'
11. Compression checks out ok


Motor starts quickly, idles fine, but bog and stumbles under load and cannot get on a plane. None of the above has significantly changed the motors behavior. The props are not dinged up, and they were on the boat when it pulled to max rpm. Final piece of data - the block is a remanufactured block by vesuvio.

My mechanic is stumped... I'm stumped. My next step is to go back through the above list and see what I missed.

Any suggestions?

Thanks,
Jim

 

[Bondo]

Re: Volvo 501b - still bogging

Is there any Exhaust Restriction,..??

 

[jimbresee]

Re: Volvo 501b - still bogging

I don't know if the mechanic checked that... I asked him to, but that was not on his list of things he looked at.

How would you get after that one a volvo? Would you pull the manifolds off the block, or pull the outdrive off and look in that way?

Thanks for your help Bondo!
Jim

 

[jimbresee]

Re: Volvo 501b - still bogging

Progress!

I was going back and re-checking things today, and made some progress.

I pulled the plugs (again) and found that that several were fouled. Apparently through some miscommunication, I thought the mechanic had swapped the plugs after he replaced the carb. Also of interest, the plugs in the boat were colder than the specified ones for the engine.

I swapped a fresh set of the correct plugs in, and the boat is now pulling much better. I guess I'll call the battle won if the boat manages to run for 8 hours without fouling out this set of plugs.

 

[Coors]

Re: Volvo 501b - still bogging

But it ran worse with a new carb...
The tech didn't realize that? When I do need a tech, mine put it in the water and test it. Tasha's-You probably know them. Jeff's Outboard.
It seems you still have a fuel problem.
The last of the good techs are retiring...

 

[jimbresee]

Re: Volvo 501b - still bogging

Hey Coors,

Good marine mechanics are hard to find. I usually do all my own work, but this 501b had me so frustrated I gave in and took it to a shop.

The mechanics a great guy, but very busy and I suspect he is as frustrated with this boat as I am.

I am hopeful that the new carb has eliminated the running rich situation. I'm going to run it for a couple of hours, then pull the plugs again and see how they look.

Thanks,
Jim