Boat no start in water...

[cuzins101]

Two of four barrels of Webber carb are not opening when at full throttle (engine off when testing). Is this normal?

[Sled600]

I know nothing of Webber carbs.....but in general, a lot if 4 bbl carbs won't open the secondary's until it is under load. They use vacuum as the key to tell them to open.

That being said, they won't open unless the engine is running.

[cuzins101]

I removed the carb and the two other barely open right up. The bi-metelac spring choke was holding down the shutter about half way. There is a mechanism that will not allow the second barely to open when choked.

I tested the bi-metalic spring with hot water and it worked. If I can adjust the linkage than I will, otherwise I need a new spring... attached is what was in the float bowl.

I must have been running on half a carb this whole time...

[cuzins101]

*not barely, meant barells. On phone...

[mmwjr]

A 4 bbl carb runs on only 2 bbls until either greater than half throttle or vacuum is reached. I think it is working fine but the choke may not be adjusted properly. When cold the choke should close most of the way when the engine has warmed up the choke should be fully open.

[cuzins101]

Originally Posted by mmwjr

A 4 bbl carb runs on only 2 bbls until either greater than half throttle or vacuum is reached. I think it is working fine but the choke may not be adjusted properly. When cold the choke should close most of the way when the engine has warmed up the choke should be fully open.

Yeah, the spring in the choke is bad. It reacts to temp, but it's warm position is too low. Causing the butterfly to stay over half way closed at all times.

Would that cause the fuel in the float bowl to look like varnish? When I dumped out the carb, I got two very different color fuels out of it (clean and clear & brown).

I have heard of people wiring in a switch to the fuel pump to "prime the system" should I consider this? How else could I get fuel up to the carb when starting after sitting for a while?

I am so tired of this..................................

[ss3964spd]

The bi-metal choke spring does lose it's tension after a while from constant heating/cooling cycles. Replace the spring.

On the carbs I know of the choke mechanism locks out the secondary side of the carb if the choke is "on". Basically, it is a preventative measure to keep a cold engine from having raw, un-atomized gas dumped into the cylinders. If the choke is not opening all the way it's likely the secondary barrels are simply not opening at all, which would definitely explain why the fuel that came out of the rear fuel bowl was skanky.

If everything is working right the carb should hold enough fuel to start the engine even if it hasn't been started for a week.

[mmwjr]

+1 what ss said, however after sitting for a week I have to crank for a few seconds to refill my carb's bowl. Once warmed up restarting is just turn key.

[cuzins101]

Well, it looks like another sea trial is going to be needed after the bi-metal choke spring replacement.

[ss3964spd]

Remember, though, it's not just replacing the spring. Once installed you need to adjust the choke when the engine is cold.

Judging rom the spooge you dumped out of the rear fuel bowl you might also consider giving that carb a good cleaning.

[cuzins101]

Originally Posted by ss3964spd

Remember, though, it's not just replacing the spring. Once installed you need to adjust the choke when the engine is cold.

Judging rom the spooge you dumped out of the rear fuel bowl you might also consider giving that carb a good cleaning.

Okay, thanks! I filled the bowl with carb cleaner and let it sit a bit and repeated unit carb cleaner came out clean. Should I use the carb dip as well?

[ss3964spd]

I wouldn't bother with carb "dip", but using a spray carb cleaner, like "Gumout" through the passages would be worth your time.

I don't know if you have taken the carb apart, but you may want to consider installing a rebuild kit if you are comfortable doing so.

[cuzins101]

Well, me and a buddy took the boat out for a maintenance run...

We tuned the carb by ear and adjusted the idle (which was low [500] rpm in the water). It is now tuned to 650-700 rpm while in the water. The manual calls for 650 rpm.

We did everything we can to get it to fail, including letting the engine cool and restarting several times.

If anybody is looking for the specs for a 1994 4.3 liter, let me know. I have the original documentations for the engine, lower unit and hull for a 1994 1800sr.

To wrap it up, there was a series of problems including a battery cut-off switch with half the cranking amperage, a bad igniter coil, corroded engine block ground, old plugs [gaped wrong], wrong exhaust shutters, gunked up carb, bad bi-metal choke, a mixture adjustment, and a idle adjustment!

Sorry this doesn't narrow the problem down for other useres, but at least give a checklist of possibilities...

Just glad it runs, like it never ran before 50 mph, at 4200 rpm WOT (before I backed it off)!

THANKS TO EVERYONE THAT HELPED!!!!!!!

[mmwjr]

Thanks for the good news report, yep all of those things combined can run you in circles.

Now enjoy the season.