Riviera Exhaust

[Petemait]

Question for Riviera owners past and present...
We are gearing up for vacation on our newly repaired Riviera. It is an '83 with a single screw 454 crusader.
The problem is, most of the time when under way, we get high carbon monoxide readings in the aft cabin. We are trying to figure out how to remedy the issue, i.e. opening or closing different windows to try and get air flow through there to consistently get fresh air in there.
Has anybody had similar issues and been able to come up with a good solution?
Thank you in advance.

One more thing to throw out there... I still have issues with the engine at idle, usually after cruising, then coming down in speed to idle speed with the engine stalling. Think it's to do with the carb...I have limited carburetor experience. Was wondering if someone could lend advice on tuning the carb. Its a 4 barrel rochester carb.
Again, thank you and best.

Pete

[km1125]

Source of the post ....
One more thing to throw out there... I still have issues with the engine at idle, usually after cruising, then coming down in speed to idle speed with the engine stalling. Think it's to do with the carb...I have limited carburetor experience. Was wondering if someone could lend advice on tuning the carb. Its a 4 barrel rochester carb.
Again, thank you and best.

Pete

Do you still have mechanical advance distributors?? If so, check to make sure that advance mechanism is FREELY moving. You can take the cap off and turn the rotor. It should move easily in one direction against a spring, and snap back. If it's sticky at all, it may stay in the advanced state when down at idle, which is too much for the engine. Once the engine dies and it gets back to base timing, the engine will run fine again until it gets to high RPMs and advances the ignition.

[waybomb]

Are the batteries under the steps leading to the aft cabin?
Over charging batteries will give off had that can cause the co detector to go off.
The charger on my 2807 went bananas and was overcharging them, and the co detector lit up

[Petemait]

KM, yes it has a mechanically advanced distributor. I will check out the rotor like you said, thank you.
Waybomb, thanks for the reply. The boat does not have a battery charger and i havent had issues with the batteries. It's definitely the exhaust circulating/making its way back into the cabin.

[bud37]

Where do your exhaust pipes exit the transom ?.......if they are near the hull sides you can extend the exit with an elbow to redirect the gasses nearer the the air flow down the side of the hull....that can help.

If you can create higher pressure inside that aft area with venting that picks up clean air from forward it will help, even on deck there can be a problem, get some CO monitors and place around, they can show maximum peak readings over time, will give you a better idea of the scope of the problem. The canvas design can also create a backdraft effect.

[Petemait]

Thanks bud. I was wondering if i'd be able to extend with some elbows. The exhaust does exit close to the sides of the boat on the transom.
We have CO monitors but we are not letting the kids go back there when we run the boat. This is tough because that is where they like to play. Maybe i will look into some sort of scoop on one side of the aft cabins on the windows?
Thanks again.

[km1125]

Source of the post .... Maybe i will look into some sort of scoop on one side of the aft cabins on the windows? ...

That sounds like a nice plan. BUT, if you do this, keep an eye on the hull splashes and which way the wind is blowing. I've run with those rear hatches open and not had issues, but I've also run where the wind was blowing strong "abeam" and all those windows (and everything below them) got soaked on that trip.

Do you have a forward hatch above the cabin area? On mine I did and you could open that up and it would "scoop" air into the boat as we were cruising. You'd get a really nice breeze into the cabin. Not sure if that would totally solve the aft cabin CO issue, but it might help.

[bud37]

Forward and aft are separated on that boat making forced air difficult....from the side deck down with ducting might work but require some engineering.
If you decide on the elbow thing make sure to add some muskrat guards while you are at it.. I made elbows from aluminium dryer duct 90's, the right size to fit the exhaust thru hull fittings....fabbed up the angles needed , locked in place then wrapped the fitting with roving soaked in resin, then painted black....was nice and light at the end.....can be made from many things but that worked for me.

Good luck with your boat and stay safe.

[Petemait]

Really appreciate the advice, guys. That idea sounds great, bud...

KM... Checked out the distributor yesterday with a friend who is good with that stuff and it was exactly as you said. We adjusted the springs and played around with it and the boat is running MUCH better now. He suggested i get a new distributor sometime this season because it has some worn parts but in the mean time we are in much better shape.
Thanks again,

[km1125]

If you still have a points distributor that would be a good time to upgrade to electronic ignition. Prestolite used to make a "kit" with complete distributor with internal electronic ignition components and matching coil and it was an easy swap. There might be other options too.