1979 Evinrude 75hp service manual help?

Joe Reeves

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Feb 24, 2002
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I don't have that manual but I'll put a entry to shove your post back to the top of the pile..... Curious as to what your problem is?
 

Cantrideslow

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Jul 19, 2017
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I need to change the impellers and I believe I have a charging issue and a timing issue
 

Cantrideslow

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Jul 19, 2017
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It isles fine and cruises fine, but when I put it in gear it does if I?m not fast enough or not holding the throttle up till the last possible second before shifting
 

racerone

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Dec 28, 2013
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You start the trouble shooting with a compression test.---Post your numbers.----Timing normally needs no adjustment for the life of the motor.
 

Joe Reeves

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Feb 24, 2002
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13,262
It isles fine and cruises fine, but when I put it in gear it does if I’m not fast enough or not holding the throttle up till the last possible second before shifting

I'm going to assume that what I highlighted in RED above is a typo and was intended to say "dies". If so, as "racerone" states above, start with the basic troubleshooting first..... compression and spark.

If the engine was the slightest bit out of time, it wouldn't run at all!

Remove all spark plugs:
Check compression... what are the compression psi readings of both cylinders?
Use a spark tester whereas you can set a 7/16" air gap or build the following (below). THe spark should jump that 7/16" gap with a strong blue lightning like flame... a real SNAP! Does it?

Removing the lower unit: First, remove the small plate on the starboard side of the long exhaust housing to reveal the shift rod connector. Remove ONLY one of the 3.8" hex head bolts. Now, removing the lower unit retaining bolts will let the lower unit drop away with the water pump being obvious.

NOTE.... When installing the lower unit, make sure that you have the groove of the shift rod aligned with the hole in the brass shift connector.

I found that I do have the entire 1979 set of service manuals but I'm not ready to part with any of them just yet.

********************
(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
 
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