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1994 175HP Oceanrunner wont go past 2500 RPM on load

T

Troutcatcher

New member
Looking for some assistance. I have a 175HP oceanrunner and it will not go past 2500 RPM on load. When you run the motor out of gear you can achieve full RPM. I had the motor completely serviced including the water pump, rebuilt all six carbs, changed oil in lower unit back in April. Have used the boat several times since the service. Two weeks ago took the boat out and initially it ran normal. I was trolling and when I went to move to another location the boat would not get past 2500 RPM. I have verified all of the throttle linkage is connected and all carbs function properly. I have disconnected the temp sensors and nothing changed. This occurs from a cold start under load. I put new plugs in the boat and nothing changed. the motor is not getting hot but this happening as soon as the engine starts. Engine starts fine, new fuel filters, new priming bulb. I am a maintenance intensive person. I am at a loss of where to go next and looking for some advise.

I appreciate any help.

Jeff
 
Start with the basics of troubleshooting.......

Remove all spark plugs... check the compression of all cylinders. What are the compression psi readings of all the individual cylinders?

With s/plugs still removed... check to see if the spark will jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! The gap is important!

(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
********************
Let us know what you find.
 
Sorry or the delay but works calls. Ok the compression on the engine is as follows:
Left Bank Top: 91 psi
Left Bank Middle: 91 pi
Left Bank Bottom: 91psi
Right Bank Top: 94psi
Right Bank Middle: 95psi
Right Bank Bottom: 94psi

Spark on a 7/16" gap was not a bright blue more real lite blue

Any ideas?
 
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