K&B 3.5 ss (gold head)

[MOTOboat]

Hey folks,

I need a little help. I finally got my tunnel in the water this weekend after 2 years on the shelf.

The boat started well had lots of torque but did not wind up to full rpm and died after about 1- 2 minutes running. The engine did not seem overly hot when I retrieved it. However I went through 2 glow plugs. They light up when the ignihter was attached but the engine dies as soon as it is removed, why is this?

I had to use old fuel from last year, the LHS said it should be fine if it has been sealed but I cannot think of another problem. Does fuel "expire"?

Also I forget what is a good starting number of turns for the CARB setting. I can't remeber (15% Nitro) just recreation running, I had it 3 turns I believe same as the previous and the motor ran awesome.

Help appreciated.

Thx

Dave

 

[TUNLBOTR]

Hey folks,
I need a little help. I finally got my tunnel in the water this weekend after 2 years on the shelf.

The boat started well had lots of torque but did not wind up to full rpm and died after about 1- 2 minutes running. The engine did not seem overly hot when I retrieved it. However I went through 2 glow plugs. They light up when the ignihter was attached but the engine dies as soon as it is removed, why is this?

I had to use old fuel from last year, the LHS said it should be fine if it has been sealed but I cannot think of another problem. Does fuel "expire"?

Also I forget what is a good starting number of turns for the CARB setting. I can't remeber (15% Nitro) just recreation running, I had it 3 turns I believe same as the previous and the motor ran awesome.

Help appreciated.

Thx

Dave

Dave,

What glow plug you are using may have an effect on it. The K&B hp plug, short--not the long plug, or McCoy MC59 works well. Beware of cheap off-brand plugs that may cause trouble.

Fuel stays ok as long as it is a cool dry place, closet inside house.

 

[MOTOboat]

I'm using the K&B 1L plug. Thats what I used previously. I had it ruining well 2 summers ago, but I did seem to always go through glow plugs ... I'll try a couple new (K&B hp short) as you suggest plugs and some fresh fuel.

I also repleaced the fuel lines also before I ran it.

Also what is a good starting for the Carb setting, the K&B WEB site says 6 turns. I seem to remrber 2 - 3/4 to 3 - 1/2, butit has just been too long and I forgot to write it down! This may be the problem as I did mess with it a bit cleaning things up so perhaps I had it too lean?

Dave

 

[John Knight]

Too lean, richen it up about a half turn. Run it until you get about 12 laps. If it dies before then, you are still lean.

 

[MOTOboat]

Thx John will do.. is it likely I did any damage?

I had been running the motor at 3 ish turns previously the motor never really got too hot... but if this is too lean is it just starving for fuel or could it be damaging the motor.

Come to think of it I am also runing it early in the year and the air is much colder now so it makes sense to richen it up a turn.

So start at 4 or 4 1/2?

Thx Dave

 

[moparbarn]

dave, prolly didn't hurt the motor running it lean in that short a time. try 4 to 4 1/2 turns, as john suggested. the air cooled gold head motors seem to lean out some, as they heat up. you will have to start rich on shore, & the motor will lean out & come on, as it heats up. around 2 or 3 laps, usually. get it adjusted to where the last 8 or 9 laps are consistent.

 

[MOTOboat]

Thx Folks

Dave

 

[Zach Davis]

Thx Folks
Dave

If its been sitting you may want to check the carb and make sure there is no gunk in it causing it to lean out.

Zach

 

[MOTOboat]

Good Idea Zack.

One last general question : I went through 2 glow plugs. they light up when the ignihter was attached (I see them glow when hooked up off the motor) but the engine dies as soon as the ignighter is removed, why is this? I would have thought as long as the glow plug "glows" the wire is not broken and they should work. I seem to have always had this trouble.

What am I missing?

THX follks

Dave

 

[John Knight]

Good Idea Zack.
One last general question : I went through 2 glow plugs. they light up when the ignihter was attached (I see them glow when hooked up off the motor) but the engine dies as soon as the ignighter is removed, why is this? I would have thought as long as the glow plug "glows" the wire is not broken and they should work. I seem to have always had this trouble.

What am I missing?

THX follks

Dave

A glow plug can still ignite and be bad under load. A key to determine that is what you are experiencing - when the igniter is taken off, the engine quits. It is weak, has a loose weld, etc. Time for a new plug.

 

[jydracing]

Hi Dave The needles on the aircooled engines are very touchy. as the engine heats up it will go lean so start off real rich and run a couple of laps to heat the engine up before adjusting the needle. What we us to do is run a k&b plug until it burnt out from being lean than put in a MCcoy and race all weekend. Hope this helps Jimmy

 

[MOTOboat]

I bought 2 MC59 plugs at the LHS. It seems in my area no one carries the K&B plugs anymore, mostly OS and MC... these were $9.50 Canadian. WOW. THe K&Bs I last bought were $4.75...

Other Glow plug manufatures I did not recognize (Dynamite or something) Is thier an OS plug that woudl work for me?

Dave