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2002 Merc Optimax 135


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Well I had the boat out over the weekend, and went to start it Saturday morning after getting the boat in the water, and it started right up, but died shortly after that. Did that a few times while waiting for my wife from parking the truck. Took off, boat seemed to run fine once past idle speed, but could only go 10 mph on the lake, due to speed limit (small state park lake).

When to return to the truck for the day, and tried to pop the boat up onto plane for a short distance, and it would only muster 3000 rpm, and couldn't get on plane at all.

My question is, would the battery be getting bad causing this issue? Bad plugs? Coil? Any ideas would be great. It died once on Leech over the 4th, but ran like a champ that entire weekened....other then when the shift linkage came off, but got that put back and and never had another issue until this past weekend. Thanks in advance for your help.

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2. Engine cranks, starts and



2.0 Low air pressure in rail See 1.2

2.1 Low fuel pressure in rail See 1.2 and 1.3

2.2 Abnormally high friction in


Check for scuffed piston or other

sources of high friction.

2.3 Air in fuel system/lines See 1.3 Crank and start engine

several times to purge.

2.4 TPS malfunction Check motion of throttle arm. Stop

nuts should contact block at idle

and WOT. Check TPS set-up. Must

connect DDT with adapter harness

(84-822560A5) to ECM.

2.5 Remote control to engine

harness connection is poor

Clean and inspect male and female



7. Speed Reduction (RPM

reduced or limited to 3000)


7.1 Low battery voltage

ECM requires 8 volts minimum

Fuel Pump requires 9 volts

Check battery and/or alternator.

Check electrical connections.

7.2 Overheat condition (engine

and/or air compressor)

Check water pump impeller/cooling


7.3 Oil pump electrical failure Check electrical connection.

7.4 TPS failure

If one (1) TPS fails rpm is

reduced to 3,000. If both TPSs

fail, rpm is reduced to idle

Check electrical connections.

TPS sensor seems to be the common denominator between the two. I can email you the maual if you give me your address.

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