Trash

You have maxed out the knock retard. 9.8 is typically the default max retard. You could increase the value but that isn't solving your problem. You have issues that likely cannot be addressed through playing with the tune alone. One last item to try just for kicks. Fill up with a tank of VP110 and see what happens.

Paxtonspeed

I have already started taking it apart. I pulled the intake off, an it looks like my intake gaskets may have been leaking a little and sucking oil from inside the lifter valley. The rubber sealing rings around the intake ports were wet with oil.
This is the gasket I used. I have researched, and it looks like these plastic style gaskets are prone to leaking.
https://www.summitracing.com/parts/m...make/chevrolet

It looks like this is the best gasket to use.
https://www.summitracing.com/parts/f...waAgo1EALw_wcB

I know if I am sucking oil that it can cause spark knock. While I may have found part of the problem. I still think I am going to swap out the cam.
The oil level on the dip stick still shows full, if its dropped at all, its just a sliver down from the full mark.

I should have put an LS in it....LOL

Trash

If you still have knock after all the gasket swapping, try a tank of race fuel (VP110 etc) and see what happens. That's an easy test.

Paxtonspeed

Will do.

Paxtonspeed

Been thinking about going all out and putting the XR282HR in it, 230/236 110-106. If it reverts water, I will MOD the exhaust. What are you guys idling at? I was idling at 600 and 650 with the current cam. How much idle speed can the drive handle? I know cold the boat idles around 900 before the computer idles it down. I am thinking with the boat having EFI, I may be able to use my tuning skills to keep chances of reversion down. Higher timing at idle, a little higher idle speed...etc. What do you guys think?

Ryan00TJ

GLM alum manifolds. Imco Performance risers. Water dumped in stock location.
355ci XM276HR 112 110ICL. Had puddles of water in center runners of manifolds after idling. Extended risers 16" to fix.

385ci 234/240 112 108icl. Same deal as before. Extended to a total of 22" past stock. This was dry to inside transom tip.

I was idling 750-850 rpms N.

From my experience your gonna have to modify your exhaust to not get reversion with that setup.

SB

if Alpha idle no higher than 800 (def under 850)


if Bravo idle no higher than 900 rpm. (def under 950rpm)

I have broken both drives various times and each (2) Alpha was due to too high idle.

Paxtonspeed

Are you EFI or carb? Do you remember timing at idle/?

Ryan00TJ

Those were carb motors. HP750.
TBIV advance module 22*. 12-14* base.

Trash

221/230 @ .050 114 LSA 110 ICL stock GLM style with stock stainless elbow. 9.45 comp. I think my warm idle is 700 but have to check. Might be 650 with a cold idle 750 tapering down to 650 at operating temp. Bravo drive. How hard it goes into gear is dependent on the prop used. A Merc Rev 4 hits the gears MUCH harder (huge prop) compared to say a High 5 or Mirage/Laser II. I'd be willing to accept a higher idle with a smaller prop.

As far as idle timing I let spark stabilization do its thing. Its dancing around all over the map until about 1000 rpm.