Merc 25hp 1800 rpm max then bogs

Barklee2

Recruit
Joined
Jan 27, 2010
Messages
1
25 hp merc 1983 idles and runs up to bout 1800/2000 rpms then stumbles above that. New plugs and carb /fuel pump kit Any ideas???
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Merc 25hp 1800 rpm max then bogs

First test is to attach an inductive timing light and watch the timing as the motor speeds up. You are wanting to see if the light begins to fail when the motor stumbles, indicating low voltage or weak spark as the ignition begins to change from the low speed windings to the high speed windings.

If the light goes out then verify stator output with a DVA Meter at that RPM and compare to the chart in the free outboard ignition troubleshooting manual available from cdielectronics.com

DO NOT order a stator without verifying the output, there is NO RETURN on electrical parts.
 

crem1

Petty Officer 1st Class
Joined
Aug 30, 2005
Messages
365
Re: Merc 25hp 1800 rpm max then bogs

Sounds like a carb cleaning/adjustment problem, and the same time you can change the fuel pump(cheap)
 
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