How many hours to clean carbs?

[Grant Brown]

1989 Merc 70hp 3 cyl.
The season before last I forgot to drain the float bowls on my carbs when I put the boat away for winter. Now it bogs and takes forever to get on plane. After 1/2 hour of running, I'll shut off the engine and let it sit awhile then restart. It then runs fine the rest of the day (or all week if I'm using it a lot). I've been told this is caused by gunk in the carbs. The gunk gets disolved by the fresh gas which acts like solvent while its sitting in between runs. When I fire the engine again it blows the disolved gunk through the system and It's fine for the rest of the day. Is there a fuel filter somewhere on this motor? I am using a plastic portable tank and there's no inline filter.

Thanks
Grant

 

[Scaaty]

Re: How many hours to clean carbs?

Try running a can of Seafoam in a tank of gas.(go a little heavy on the mix

 

[WillyBWright]

Re: How many hours to clean carbs?

Fresh gas won't dissolve varnish. And don't use additives to try to solve your problem. As it's running lean, your motor is being damaged, possibly to the point of needing an overhaul before any aditives have a chance to work. It's about a 2Hr job for a shop. You might get lucky by just cleaning the main jets which are in your carburetor drains, but I'm not sure the risk of not doing a complete cleaning is worth it. What's probably happening is that bits of varnish are breaking off the surfaces and causing occasional temporary blockages. Your motor gets it's lubrication from the oil in the gas, so fuel starvation is lubrication starvation. There is probably a fuel strainer on the fuel pump.