1988 Evinrude 90 HP runs but no power

cstorz3

Recruit
Joined
Aug 20, 2009
Messages
1
The engine starts and idles OK, but has very little power. I do not have a working tachometer but am guessing it will only turn about 1500 RPM under load at WOT. It will rev up quite high when out of gear when using the fast idle lever, but it has to warm up a bit before it will rev up even then. Any help you can give me?:confused:
 

Bifflefan

Commander
Joined
May 27, 2009
Messages
2,933
Re: 1988 Evinrude 90 HP runs but no power

sound like your missing a couple cylinders.

do spark and compression tests.
thsi should tell the tale.
 

bktheking

Vice Admiral
Joined
Jul 29, 2008
Messages
5,057
Re: 1988 Evinrude 90 HP runs but no power

She's only firing on 2, they rev up great in neutral but put em on the lake and it's like an elephant is in the boat. Connect it to muffs, run it for a while and put your hand on the cylinder head, the cold one has no fire.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1988 Evinrude 90 HP runs but no power

Start by checking to see if you have good spark to all 4 plug wires. When the engine is warmed up, put an inductive timing light on each wire. This should show plug misfires or nofires. Or- when running, you can pull the plug wire off each spark plug. As you do that, listen to the engine. If you pull a wire off and the engine does not slow down at all, that wire/plug is probably not firing.
 

Tbankston

Recruit
Joined
Feb 29, 2012
Messages
1
Re: 1988 Evinrude 90 HP runs but no power

I had an '82 Johnson 90hp that would cut in and out at any throttle above idle. The machanic replaced the stator coil and one power pack. I was told that even with good compression, perfect timing, and even the appearance of spark when grounding a plug; the stator and power pack sometimes will not produce enough power to reach max rpm. It is possible to measure the stator and power pack output to verify proper levels. Hope this helps.
 

archcycle

Chief Petty Officer
Joined
Sep 21, 2009
Messages
647
Re: 1988 Evinrude 90 HP runs but no power

+1 cylinder drop. More than likely it's a spark issue but if you do find you have spark on all 4 (seriously doubt it) then premix some fuel/oil in a spray bottle and spray it down the carb throats and see what happens.

To find out what's going on here you will need a spark tester, cheap at any auto store, and a compression tester, cheap from places like Harbor Freight or eBay but expensive at auto stores. Follow the spark and compression testing instructions in the Top Secret file at the top of this section of the forum.

Post results.
 
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