Johnson RD18 help needed!

gjonz

Petty Officer 3rd Class
Joined
Sep 20, 2008
Messages
76
I finally hauled my first of two RD-18's out of the basement. I tried to start it, but no dice.

Here's what I have done so far in troubleshooting.

1. Good compression
2. Good spark on both cylinders (Checked with spark plug air gap tester.)
3. Good pressure fuel tank - holds pressure and pumps gas. (double checked)
4. New fuel lines and fiber filter in the bowl.
5. Carb rebuilt with new needles and packing.
6. New plugs properly gapped. J6C plugs.
7. New condensors, coils, and points - gapped and cleaned.
8. Opened carb to double check all passageways. All okay.

Now the issue:

1. The motor will not start or even act like it wants to.
2. Checked new plugs, they were not wet.
3. Pulled carb, and checked float (new) and the bowl was not damp with fuel.
4. Sprayed mix in the carb, motor will run briefly...very well I might add.
5. Then dies within seconds.
6. Disconnected the vacuum cutout just to make sure it was not creating issue. No problems.

So I have spark, compression, and fuel into the fuel filter, but not to the bowl as far as I can tell. Obviously a fuel problem.

Anything obvious I've missed. I can't see much value in carrying pre-mix in a bottle to spray in the carb on my way down the river.

Please help me get my firs motor running.

Thanks!

Greg
 

CATransplant

Admiral
Joined
Feb 26, 2005
Messages
6,319
Re: Johnson RD18 help needed!

How's your pressurized fuel tank? Does the primer button work properly? Does the tank hold pressure? Are the O-rings in the connector OK? That's a common problem for fuel delivery.
 

coolguy147

Commander
Joined
Jul 14, 2008
Messages
2,817
Re: Johnson RD18 help needed!

u know u have to prime the motor to get fuel in there right...:confused:
 

gjonz

Petty Officer 3rd Class
Joined
Sep 20, 2008
Messages
76
Re: Johnson RD18 help needed!

Yep...fuel tank and connector was rebuilt and using a nail in the connectors fuel side, and pumping the primer button would have made Jed Clampett a rich man.;)

Pressure is maintained until the cap is loosened.

I just knw when I get it running...I'll kick myself.:rolleyes:

Greg
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: Johnson RD18 help needed!

If you pull the fuel line off at the carb and then pump the tank does fuel come out? Would Jethro be happy also?
 

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: Johnson RD18 help needed!

1. The motor will not start or even act like it wants to.
2. Checked new plugs, they were not wet.
3. Pulled carb, and checked float (new) and the bowl was not damp with fuel.
4. Sprayed mix in the carb, motor will run briefly...very well I might add.
5. Then dies within seconds.

Sounds like the float is stuck. If you pull the fuel line off right at the carb, does a stream of gas shoot out, soaking everything before you remember to de-pressurize the tank? :) If so, then the float is stuck.
 

56 rude

Banned
Joined
Aug 8, 2008
Messages
198
Re: Johnson RD18 help needed!

Sounds like the float is stuck. If you pull the fuel line off right at the carb, does a stream of gas shoot out, soaking everything before you remember to de-pressurize the tank? :) If so, then the float is stuck.
make sure the bottom of the carb isnt blocked for some reason ,the fuel has to go from the glass bowl into the carb if everything else is ok.if i understand you correctly there,s no fuel in the carb atall right?i see you said you put on new lines ,not backwards are they?
 

gjonz

Petty Officer 3rd Class
Joined
Sep 20, 2008
Messages
76
Re: Johnson RD18 help needed!

Double checked the fuel and air lines. All ok.

Seems that the fuel is not getting from the filter bowl to the carb bowl at the bottom.
 

jbjennings

Captain
Joined
Jul 18, 2007
Messages
3,903
Re: Johnson RD18 help needed!

I think your float needle is stuck also. OR, it could be that darned fuel filter inside your glass bowl is bad. Try removing that fuel filter element and see if that cures your problem.
Good luck,
JBJ
 

R.Johnson

Rear Admiral
Joined
Sep 24, 2003
Messages
4,446
Re: Johnson RD18 help needed!

Remove the bottom high speed jet, fuel should pour out of the bowl. If not, fuel is not gettine past the needle, and seat.
 

gjonz

Petty Officer 3rd Class
Joined
Sep 20, 2008
Messages
76
Re: Johnson RD18 help needed!

All fixed and running! It was the needle valve in the carb that was replace, but hanging up in the closed position.

She runs, pumps water, stays cool to the touch, starts right away.

Now with some minor fidgeting with the mixture, she'll be a runner!

Thanks for all the help!

Greg
 

56 rude

Banned
Joined
Aug 8, 2008
Messages
198
Re: Johnson RD18 help needed!

All fixed and running! It was the needle valve in the carb that was replace, but hanging up in the closed position.

She runs, pumps water, stays cool to the touch, starts right away.

Now with some minor fidgeting with the mixture, she'll be a runner!

Thanks for all the help!

Greg
good going.
 
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