totally confused!!!!!!!

[jodymartin]

Boat&motor- 1986 21' bayliner capri-aq225e #cu56837.....

new carb, dist, dist cap, plugs, wires, rotor.... timing set at 8 degree btdc at 600rpm....
engine idles great at 700rpms.... put the boat in the water under a load and it runs fine up to 3000rpms then the secondaries open and it boggs down.... if i pump the throttle it will catch up and run fine at 4200rpms for as long as you want it to but if i slow down same issue....

now with someone else driving and they go to wot.... if i turn the dizzy while the engine is bogging out it will run great all the way from 1300 to 4200 rpms... but it has a loud tapping noise sounds like the lifters and idles rough....

any help will be great

 

[Don S]

Re: totally confused!!!!!!!

You need to set your timing where it should be, then check your advance to make sure it's working.
A compression test would be a good idea too.

 

[jodymartin]

Re: totally confused!!!!!!!

thanks Don. do you happen to know what the compression should be on each cylinder? when the timing is set and i rev the engine it does advance from 8 degrees btdc to about 30 degrees...

 

[Don S]

Re: totally confused!!!!!!!

Here is a service bulletin from Merc (GM really) the Volvo bulletin was almost word for word, but I can't find it.

http://www.boatfix.com/merc/Bullet/97/97_25.pdf

 

[jodymartin]

Re: totally confused!!!!!!!

how much should the dizzy advance????? whats the easiest way to measure it?

 

[Don S]

Re: totally confused!!!!!!!

it does advance from 8 degrees btdc to about 30 degrees...

That is what it should be, best way to check it is with an advance timing light.