Not enough air in outboard motor well

[Bob Muggleston]

Hello, sorry if this has been covered to death, but I'm finding that I can't operate my outboard with the lid of the well closed. Is this common on the Ariel/Commander? The cutout access for the engine controls is fairly large -- seems like plenty of air should be entering the well through it, but every time I close that lid (it's so quiet with the lid closed!) the engine rpms drop, probably within 30 seconds. As soon as I open the lid the rpms jump right back up. Very frustrating. I have a nice little Yamaha 4 hp 4-stroke with a power prop on it -- would love to be able to cruise and talk to the folks onboard at the same time. Right now that's not really possible. Any clever fixes out there?

[ebb]

In response to a Pearson Commander with a similar problem to yours:

"The solution is to provide a dedicated fresh air supply to the engine that originates from
outside the compartment.
Running a flexible 3" vent hose from the clamshell vent on the aft deck adjacent to the
compartment to the engine itself does this.
You will need to modify the engine with a permantently attached PVC pipe and elbow that
will allow the engine to take in clean air without water.
PVC pipe is sized for the vent hose to slip over and hose clamped. This will allow you to
disconnect from the engine when you take it out of the compartment.

Design system so flex hose doesn't get crushed when tilting engine up for sailing -- or
remember to disconnect hose when under sail.
Outboards have different locations for fresh air intake, usually under the engine in front of
carburetor. Attach PVC with epoxy or screws.
Use a permanent method of attaching flexhose to clamshell vent. If it can fall off it will."

Originally written by BillSandifer, G.O.B. Feb, 2005 .............(compressed a little by ebb)

Hope this helps with ideas. Good luck!

Might also check to see that you have plenty of fresh air circulating in the compartment
and your exhaust is not collecting in there. Is the motor shaft long enough? I had a
Yamaha 8-4 and thought the extra long shaft was barely long enough! If you decide
to force air, do not wire any fan inside the compartment, gasoline goes boom.

[SkipperJer]

This is a common problem discussed many times on this forum. There is no perfect solution. I'll tell you what works for me.

I have a 70's vintage Johnson 6hp long shaft motor. I remove/replace it everytime I sail so it doesn't foul. It's reliable and weighs 45 lbs so it's manageble. It has a slot about half way down the aft side of the shaft where the cooling water and exhaust come out. I jam one end of a 36"-48" piece of 3/8" clear plastic tubing into the slot. I afix the hose to the shaft a little below that with a cable tie pulled just tight enough to hold it against the motor. The other end of the hose usually ends up just below the surface about 24" BEHIND the stern. I can see the water bubbling through the clear plastic hose at the shaft to verify cooling. The exhaust comes out well enough away from the motor well that it doesn't foul the motor. Sometimes motoring downwind exhaust still gets into the cabinet. I have learned to compensate by steering a long, lazy "S" course. I've added that to my list of sailing skills.

I have seen all manner of 12v fans rigged (nobody blew up) and none of them worked reliably. I considered trying to feed fresh air directly to my motor but there was no easy way to fit anything to my engine cowl that wasn't complicated and clumsy. This is simple, cheap and works but keep in mind it may be specific to my motor. My winter engine maintenance guy says its not harming my engine. Plugs have always looked good.

[SkipperJer]

FYI. After a certain amount of use the hose clouds and its hard to see the water bubble by. I replace it once or twice a season.

[c_amos]

Ariel Spirit (#3) had a bilge blower plumbed to force air in while the lazy-rat hatch was closed. It worked, but drew a lot of current! I also had water enter the boat in a storm on the Chesapeake (hose passed through the aft bulkhead).

I think the 'hose on the exhaust' trick is a better option.

[ebb]

Who? say, Muggleston...