Picked up a new Crestliner SuperHawk last year with the Opti, I am finding with the centre windshield closed, it sure creates a draft and sucks the exhaust into the cockpit. Other than keeping the centre windshield open, are there any cures? Thanking you in advance.
On mine Tuffy with a walk thru I dont get exhaust smell but when I get close to 60 it starts sucking water mist forward a bit, with the windshield open nope.
This is really interesting, imagine if boat designers need to start running wind tunnel tests to see how exhaust fumes may get sucked-back in to the cockpit area. I wonder if a wave-wacker type “deflector”, mounted across the transom, would influence the airflow enough to prevent the suck-back? No wonder why so many wheel-boat drivers tend to act so ditzy! 
But, all kidding aside, this could really lead to a serious problem. You may want to file a report with the USCG and see what kind of response you get. http://www.uscgboating.org/recalls/owners_report.aspx
HRG
I’m thinking of the open air gap below the “door” in the windshield … perhaps you could either open or close (with a piece of snap-in vinyl or something similar) that space to change the airflow?
my friends 17.4′ boat does that as well but mine doesn’t, I also have a 19.5′ boat with a larger motor. Maybe you just need a bigger boat. Seriously though I wish I knew the fix, if you find one let me know so I can pass the info along.
Stop driving in reverse 
Glad I could help 
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I’m thinking of the open air gap below the “door” in the windshield … perhaps you could either open or close (with a piece of snap-in vinyl or something similar) that space to change the airflow?
That gap has always been open, I figured that it would put airflow through the boat and thus not create a vacuum. Perhaps my tinking is flawed. I will close it off next time.
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Stop driving in reverse
Doing what John23 said was my idea too as I also get suck back mist when my windshield is closed. This would definitely change the airflow but could create more drag or wind resistance.
I wonder if the wave wacker idea will work. Let me know if you figure it out.
Eric
Maybe found out the problem. The Powerhead is scratched up and one piston is completely pouched. The dealership ordered a new powerhead from Mercury. Maybe the fuel wasn’t burning clean and complicated the problem.
Sounds like a cold seizure occurred-one of the biggies with opti’s. Combat this by ALWAYS letting the motor warm up to proper operating temps before WOT and using good quality DFI oil. From everything I’ve read and heard from others that know much more than me, always let the thing warm up.
Good luck and glad you are on your way to getting it fixed.
As best as I can remember I had always let it warm up some before moving, and especially before WOT. But how would you know if it was up to temp. I do not recall seeing a temp guage.
Invest in a Smartcraft Moniter, well worth the investment, even though you let it warm up, you may have a stuck stat or something stuck in it. And all watercooled engines need proper warm, if you snowmobile there are allot of cold seizeres there also
none of those recommendations will matter.
It is the reaction of dissimilar metals in the motor that expands/contracts at different levels/speeds.
This is what causes the Optis to pop.
I used to be involved with the manufacturing of the fuel delivery system with these motors.
Gary,
Is the problem the same for the E-tech’s, as their big motors were blowing up as well?
From all the info I have read and been told by reliable sources, the 200-250 opti’s were the real culprits and less with the lower HP models. I have heard from more than one source (dealers, mechanics) that my 135 is very stable far as opti’s go.
Doc;
You are correct.
The vast majority of the problems are between the 200-250. From my un-educated interpretation from a reliable source is that the between the jug/block or head/block, the metals are of two different types. They heat/cool (expand/contract) at different speeds/levels. This causes the issue with them.
NOT everyone, this will happen to. But the VAST majority of the time, that is the problem. When that isn’t the problem, the fuel delivery system fails for various reasons, which causes the blow.
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