Questions Re: Carby 'lock Patch' Screws And The Drain Hose

[wonniefisho]

Hi all,

Just doing some things to my motor, and have 2 questions.

After reading the workshop manual it mentions something about the 2 'air silencer' base screws at the bottom of the carby and that they need to be discarded and replaced when they are removed. Can I get clarification as to why? Not sure if they are original or not but the 2 bottom ones on mine were the same type of standard looking bolts as all the others holding the base onto the carbys.

Secondly, the drain hose at the bottom of the air intake - I assume this is to drain any water that might get in? And if so, where does the hose that disappears under the motor itself go to - the reason I ask is that the hose is split about an inch back from the the base cover - if it just drains it away and goes nowhere I won't worry about it.

Thanks all.

[a boat]

Hi, the reason you want to use new screws and loctite them in is because if they vibrate loose they can easily go thru the carby venturi and best case get stuck in the reed valves causing the engien to run bad if at all. Worse case is that the screws find their way into the combustion chamber and do big time damage.

The drain hose is not for water, if you are getting water in there it will also be sucked into the engine, what it is for is to drain any excess fuel back into the crankcase. this can happen when the engine is trimmed up or if the carbys flood and is a safety factor. Replace the hose if it has a split.

Cheers,

Huey.

[wonniefisho]

Hi, the reason you want to use new screws and loctite them in is because if they vibrate loose they can easily go thru the carby venturi and best case get stuck in the reed valves causing the engien to run bad if at all. Worse case is that the screws find their way into the combustion chamber and do big time damage.

The drain hose is not for water, if you are getting water in there it will also be sucked into the engine, what it is for is to drain any excess fuel back into the crankcase. this can happen when the engine is trimmed up or if the carbys flood and is a safety factor. Replace the hose if it has a split.

Cheers,

Huey.

Thanks Huey, you're a legend. Looks like I'm going to be busy again today. I might use this new boat one day!!

[pelican]

Hi Mate

Have you done a compression check on that motor. Just asking as if there is a problem with the hose it may have run lean on the bottom pot as air would have been going into crankcase. It may have also affected a smooth idle so if it was idling fast it shows that someone who didn't diagnose it properly adjusted it up to hide the problem.

When down the track you do lift the head in general maintainance have the bottom bore looked at closely as it will tell if there was a problem for any length of time.

Last one Its unlikely but worth checking - if there is water in that tube- I would after the next few short runs pull the plugs. If the bottom plug is especially clean compared to the top plug you may have a leak enabling water to get in which will need immediate attention. Small amount of water acts like a steam cleaner and leans up the cylinder and plug.

If the bottom plug is really carboned up it is time for carby adjustment. Check your other fuel hoses for softness as spliting can be a sign ethanol fuel has been used.