Can't say I don't love the power so far but I'm gonna need some help/opinions on getting it dialed in.
Did a cam
Mikuni with 25 pilot 167.5 main 97 needle in middle clip
Bps duals
Heads decked .040 4700 rpm springs with shims and Ss valves
No port or polish

Things I like :
Hole shot is retarded fast
throttle response is nice
Gained top end speed

Concerns:
Gained 2-3 mph but I'm still only running 3900-4100 rpm
If I trim up a little where I used to run it before mods I can turn 4600 but it's not gaining much speed if any at all. Also the tiller arm is about to throw me out of the boat at that point
It kinda stutters a little going off idle onto the pilot but pilot to main is a smooth transition.
But it kinda bogs all the way through the mid range.

A few small hooks at transom that I'm going to knock out might help something.

Blowing oil out valve cover gasket the on breather side
Also after running a while when it starts up there's a puff of black smoke out that side.

This is all I can think of for now.
It's a 35 gdsd on 1860 Godevil boat.
26 deep with two men but I could hit 28 in a chop and shallow
28 deep with just me but hit 30 shallow.
I know these are good speeds but this is only at 3900-4100 rpm but trimming up any more is hard to hang on to.


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Adjust AP pump till cam lever is "just" touching, try AF screw between 1-1/4 & 1-1/2 turns out so if ya blip it it comes up crisp and then idles down normally "w/o lagging" may hafta bring the clip down one position but prolly not. You might get a smidgen more top end by running the valve lash a tad tighter too. Black smoke is fuel and one side is richer. What exhaust? The more open the exhaust better for the top end, slightly restrictive won't bother bottom but will on top.

Just saw the bps duals so nevermind that last part

The baffled duals were pretty restrictive.

10-4, I was thinking those were just small glass packs... Remember when tuning the carb bog is lean, blubber is fat... Makes it easy to remember!

It's a 310 plus four on the cam if that makes any difference to anyone else who's trying to help him.

You should base your gains on what you had before. Saying you should be running "X RPM" or "more RPM" isn't exactly accurate. You said you gained several hundred rpm and several MPH, I'd call that solid gains. Get your carb tweaked and you may see more. I can't really speak on the exhaust but I would assume there is a reason they were redesigned.

Makes sense to me. I run my prop right at 1/2 in 1/2 out. Water is right at the middle of the lower seal housing. I know some run a GDSD deeper, more like 2/3 in but I find mine has much better top end that way. It does handle a bit better trimmed down some. My tiller tq doesn't get bad until I'm so far trimmed up the prop is losing bite anyway. It turns right at 4K up on step and pretty much has since it was new. In shallow water it gets up to around 4200. Bone stock 37 on the same frame and hull you're running. The stock 3 blade GD prop on the 37 feels "right" on another identical boat with a stock 35 it felt like it was working its ass off to turn 3600.

You running 34 top 48 bottom on the belt pulleys?

I have a buddy that has the dual exhaust.
Once he took them off and replaced muffler his motor ran 100x better. Worth a shot

A gutted stock will probably flow better than the duals.

I think that's your issue

I put the duals on the engine in stock form and picked up a bunch of bottom end from the gutted stock. Didn't realize i was gona hurt top end.

What if I take the biggest drill bit ive got and drill some holes in the baffles


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Do it

Make sure you clean it out well. You don't want to take a chance on getting metal shavings in your motor.

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Like I said before I'm not familiar with those cans so if you can get to the baffle you can definitely drill some holes in it to improve the flow. I would take 'em off if there's ANY chance of slivers getting into the port. some of the baffles I've done used two or three different sized holes, like three 1/2" and three 3/8" then some 1/4" in between this was in a circular pattern. The bad thing is you'll usually have to over do it to figure out where the happy medium is between performance and sound.

Just bang them on the ground until the baffles come loose and fall out.

I have no idea man. Don't listen to me. Sorry.

i drilled a set out with a 3/8 bit 18 inch longs. go slow got 2 passes all the way thru but the last hole on the last past finished the bit off because i believe it stainless in there.

I have found the 167.5 to be to much fuel on most engines. 165 should help...I would think you should be getting mid 4,000's for RPM's though with those mods.

I have ran that very same cam, with heads and gutted stock exhaust was turning 4,700 on a prodrive. I wouldn't think you would be that much off with a GDSD...

Your gonna get black smoke out of exhaust if running too rich. I really think it's the duals not flowing well

Anybody know if these are the more restrictive baffles or not? I'm assuming they are.


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