We just got a 1989 Seaswirl 18' 4.3L Chevy v6 with a OMC outdrive. The boat runs great when you first put in the water. After running it for 20 or 30 min or so, we stopped and shut it off for about 30 to 45 min. I fired it back up and started off and just as it was coming up on plane it would start spitting and sputtering really badly and even choked itself off once. It would start right back up and come up on plane and run fine. Shut it off again for 30 min or so and start it back up again and the same thing happens again. Seems after it get's rid of the sputters it does fine. Does anyone have any ideas?

Thanks

Plugs fouled?

Could be vapor lock. You can try idleing for a couple minutes before you shut down to allow some of the heat to dissapate and run the blower while the engine is on.

Keep your eye on the temp guage and if you do not know when the impeller was last changed then plan on changeing it this fall. Not too tough to do and needs done every couple years or so.

Those are great boats. Just get a manual for your engine/drive combo and welcome to the boards.

Make sure none of your fuel lines have be rerouted to where they are exposed to excessive heat.

It could be your choke needs adjusting, and/or the electric choke unloader is disconnected or not working. (I'm assuming you have an electric unloader, nearly all carbed boats do) Boats engines don't get very hot, and the choke can close after sitting 1/2 hour. If it's adjusted towards too rich the carb can severely overload a warm engine. If the unloader isn't working, it will rely on engine heat to open the choke which can take several minutes longer than if it WAS working. A warm engine does NOT like being choked!

Since your boat seems to get over it quickly, IF the choke is your problem it sounds like it just needs to be adjusted...

To check adjustment-- next time you've sat for 1/2 hour, WITH THE KEY OFF put the stick in forward and push to about 1/3 throttle, then return the stick to neutral. Now pull the flame arrestor and check the choke plate. If it's nearly or all the way shut, it needs to be adjusted, as should only be about 1/2 way shut MAXIMUM a half hour after running.

To check the unloader-- this is best done with a cold engine. First, verify the hot wire is connected. It has an electricially heated coil that comes on when the key is on. Simply turn the key on and watch the choke plate for about 3 minutes, it should be visibly opening by then. (my chokes are almost fully opened in 3 minutes)

Just an aside, one thing I've found almost completely useless on a boat is a choke. Because boating is done in warm weather, you really don't need the choke, even for a cold engine. Some people (GFC ) boat in cold weather, so a choke will be necessary. Me, I have my chokes on the houseboat engines set so at around 60 degrees they only shut half way. Since I've adjusted them that way, they start better and are easier to keep running on a cold start. And starting them warm is just a blip of the key, and they're ready...

Griz, just wanted to say welcome aboard the finest boating forum on the net.

Also, keep this in mind...

Wait, that's a lead in to you sig about boating safty courses, isn't it?

Yup...

"We just got" and "having troubles" is a common theme.

If you have not done a thorough maintenance on the engine, then do so, This will give you a starting point. Based on the age of the boat/engine, I would check the following things:

New fuel filter
Spark plugs
Distributor
Fuel Tank Venting
Carburator - clean - check choke linkages, etc.

Based on your description, I would go with fuel tank not venting properly. The problem is, it could be a number of things, so start the process of elimination.

Thanks so much for all your input. I am going to take it to a friend that owns a boat sales and servies and have it totally chacked out and tuned up. Again, thanks for the warm welcome.

Update. The boat just kept getting worse and worse until it reached a point the she just barely ran. After getting the WATER out of the tank, filter and carb. she runs along at 41 mph at 4600 rpm's. I guess the water just dosn't burn nearly as well as gasoline does. LOL