No top end power

[shirthero]

Ok, recently aquired a 71 johnson 60 hp on a 16ft v-hull glastron. Starts easy, idles pretty well, put it in the water and cruise-just about 5 mph! Never planes, never devlops over 2000 rpm (guessing no tach.)
Compressions- 120,120,120.
Spark is strong bright white, plugs are new.
No. 1 plug is a nice light brown and dry
No. 2 & 3 are slightly wet and oily.
Took the carbs off and opened them up, very clean, look to be recently rebuilt.
throat of #2 has some visible fuel mix on the bottom of it
throat of #3 has more still
Reeds-1 and 2 clean and new appearance
#3 reed looks same but has a decent amount of fuel/oil standing on them.

Any thoughts? #3 way rich?
# 1 not getting enough fuel?
Could it just have the wrong prop?
HELP!

 

[samo_ott]

Re: No top end power

Have you checked the linkages and cables? With the engine off, move the throttle to full and see if the throttle butterfly's in the carbs are horizontal. At least make sure thats working, also make sure that the ignition is advancing at the same time with the increased throttle.

 

[tashasdaddy]

Re: No top end power

welcome to iboats, do as above, recheck the carbs, sound like floats on 2 & 3 are high. http://forums.iboats.com/showthread.php?t=244013

do a link & sinc. besure timing plate is moving freely.

is the arrow on the fuel primer bulb pointing toward the motor, vent open on fuel tank.

even possibly bad throttle cable.

 

[Jacob645]

Re: No top end power

Diddo td. Any cracks in the coils? Underneath? Any "aftermarket silicon"? I have a 1975 50hp that did the same thing. Do a cylinder drop test to make sure all of them are firing fine. Mine actually did ok with the cyl. drop test but i bought a couple of new coils on a hunch and it runs like a dream now. The spark was great at idle but at higher speeds it wasn't producing enough. Just something to check! Also check your timer base to make sure it's advancing fully to the stop. It should advance BEFORE the throttle does. Are your plugs gapped correctly?

 

[jtexas]

Re: No top end power

Plugs should have a light coating of oil after idling, I'd worry about #1.

You described a classic symptom of clogged hi-speed jets.

But first do a spark test. Should jump a 7/16" gap with a strong blue spark. Don't use the spark plugs to test spark outside the cylinder, it doesn't tell you anything.

You have good compression; if spark checks out, rebuild your carbs. You can't tell by looking whether they're clean because you can't see inside the passages.

Welcome to the forum!