1989 Sea Ray (Mercury / Mariner) 100 hp poor performance

baloo6049

Cadet
Joined
Jun 10, 2010
Messages
12
My 89 Sea Ray outboard 100hp has multiple symptoms. (Boat is a 1989 Sea Ray 160 Bow Rider)
1. Hard start when cold
2. WOT it only gets to 4500rpm when is should be 5000 - 5500.
3. Oil and temp alarms sound when engine is cold and not running.

Things that I have done.
1. new prop. Factory spec is 12 3/4" x 23 pitch. That is what I put on it.
2 Replaced fuel line from tank to the engine, including primer bulb and inline water separator and filter.
3 Replaced inline fuel filter after fuel pump
4 Drained the oil tank and checked for debris, it was clean.
5 Checked resistance from "Oil Warning Module" (Tan and Black wires) checked out ok. Also tested leads to the oil tank, No resistance when tank is full, infinite resistance when the tank is empty.
6 replaced water pump. Water streaming out of the "pee-hole" is good.
7 Idled engine with muffs on it and was able to touch it easily. Checked the temp with my meter and it was in very low, in the 90's. Only let it idle for a few minutes.
8 New battery
9 Replaced thermostat.

One interesting thing to note is that the alarms did not start until the key was left on over night.

Any help would be greatly appreciated.

Just changed spark plugs too. did not help with engine performance.
 
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