caddydaddy472

The K&B 7.5 in my boat seems to spray a lot of fuel/oil out of the carb, covering the tank in oil and leaving a few ounces in the bilge after a run. Would something like an intake tube they use on nitro cars help keep the spray in the motor? Any suggestions on what to do?

Ron Olson

My Feedback: (1)

If it's leaving "a few ounces of fuel" in the bottom of the boat then possibly it's way too rich as it shouldn't be spitting that much back from the carb.
You can use a snorkel type of intake tube but keep in mind that the ones used on RC cars also has an air filter to keep it from inhaling dust.

caddydaddy472

I wouldn't use the filter, but I don't think it's too rich.  I keep burning out glow plugs, so I think it's still on the lean side.  I have less than a gallon through the motor, so I'm still fine tuning it.

advanced builder

I have a aftermarket metal fuel tank for my rigger. I have to keep a towel covering up my tank in the heat of the day. Fuel runs out the carb just setting. Fuel tank sets higher than the carb. So gravity works on the fuel. Not so with a rear exhaust engine,the carb sets up higher. yes it happens

caddydaddy472

I don't think it's expansion.  I keep the fuel lines plugged until I'm ready to run it.  Then I'll hook them to the carb and exhaust and run it.  When I get the boat back, the fuel tank will be covered in oil!  

caddydaddy472

Here's my idea! I'll test it out soon and hopefully it works well!

HendricX

If you're burning plugs .... put on an extra copper ring on the glowplug-threads.

Or lift the plug-head and campher the "bowl" .

amax

If your blowing That much fuel OUT the carb you may need a Colder Plug or Lower Nitro or Less Compression. Sounds like the Timing is advanced a litte and the Fuel is Preigniting. Since these engines have no Distributor, Coil, Spark Plug ect.. Ignition Timing is controlled by 4 things: Compression Ratio, Nitro %, GlowPlug Heat Range, Air\Fuel Mixture.

rcguy1411

Lean will tend to suck the electrode out of the plug and rich tends to crush them how are your pluhs failing what are your carb settings

advanced builder

One of my fellow boater has a plastic 1/2" 90 degree pipe fitting on the carb. If you cut 1/2 the plastic hose off ,you will be OK Just looks long to me. If it works good job.