no top end

[all8up]

A few months ago i purchased a 1969 richline 14ft aluminum v bottom with a 1970 evinrude 18hp fasttwin. It hadnt run in a few years so the fuel system was nasty. I rebuilt the carb, cleaned the plastic fuel tank and replaced the fuel line and primer bulb. I also replaced points and condensers. Starts right up and idles great and runs smooth, but at wot it sounds like its maybe only getting to 2000 or 2500 rpm and of course has no power. I pulled the carb agian and rechecked the main jet, seemed fine, but i sprayed and blew through it anyway. Tried bulb pumping, didnt change anything. Any fresh ideas would be greatly appreciated.

 

[Joe Reeves]

Re: no top end

Normally, if a high speed jet is restricted, the engine will bog and die out when throttle is applied. For what it's worth, I always clean that jet with a piece of single strand steel wire as solvent just doesn't do the job properly.

I would suspect that the carburetor throttle butterfly isn't opening fully, OR a compression/spark problem exists, OR the armature plate upon which the points etc are attached has a bad wobble to it which will change the point setting as the armature plate advances. Let us know what you find.

 

[CatfishMN]

Re: no top end

Welcome to iBoats. I see you said you did the points and condensers, but what do the coils look like? Not saying to automatically replace them, but definitely take Joe's advice and check spark. Sounds almost like you are dropping a cylinder.

 

[all8up]

Re: no top end

I checked the spark on both cylinders and it was great while cranking.(electric starter made it easy to check) The plate does wobble some, what causes that? I have been an auto tech for 25 years and I thought this motor would be easy, Its proving otherwise.

 

[all8up]

Re: no top end

And i did verify that the throttle opens fully.

 

[Joe Reeves]

Re: no top end

(Magneto Armature Plate)
(J. Reeves)

If the armature plate has a a loose fitting, wobbling motion (the plate that the points, coils etc are attached to), it is usually caused by a slightly worn support ring. This allows the point setting to change erratically as the armature plate turns.

The cure is to remove the armature plate so that the support which is attached to the powerhead with 4 screws is visible. Then, with a screwdriver and hammer, or some tool of your choosing, and looking straight down at the support ring, make an indentation at what would be called the 12, 3, 6, and 9 O'clock positions. Install the armature plate and check for a smooth turning wobble free movement.

You may need to do that procedure a few times to obtain the proper fit (not too tight, not too loose), but it's worth the effort.

Use a small amount of anti corrosive grease between the aluminum ring and the brass support plate and also on the brass bushing of the armature plate when all is well.

Spark plugs should be Champion J6C plugs gapped at .030.

 

[all8up]

Re: no top end

Thank you very much. I will address this and post how it turns out. I really appreciate the advice and enjoy reading this forum.

 

[all8up]

Re: no top end

That was great advice. I tightened up the armature plate and the motor came back to life and runs great. Thanks so much for taking the time to help me out.