Evinrude 7.5 idle

[crosbyman]

could be….” clean the carb” don’t mean much I guess…. one presumes it was adjusted…right ?

time for a blow test if not a downstream issue 🙂

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[lloyd]

The three paramount factors for engine performance are: Compression, Ignition, and then Carburetion in that order. Why waste time and money building a proper ignition for a motor with low compression??? Why waste time and money rebuilding a carburetor for a motor that has no ignition????

[crosbyman]

without answers to most above ??? it is all a guessing game. carb and ignition apparently done ?? compression #s still unknown hopefully good enough . we don’t even know if this is a new problem , a new to me engine…etc…

patience brings joy

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[outbdnut2]

Does the idle change at all when you adjust the low speed idle needle? If it does not change, that is a big clue.

Can you find a choke setting that makes it idle better – another big clue.
Dave

[james hobson]

Ok I get it i will check compression is a simple screw in the cylinder pull the rope good enough or should I do a leak test, should motor be hot warm cold, can you run engine on one cylinder and check other one for compression check any tips would be helpful, thanks

[james hobson]

Will check compression any tips on how to check would be helpful

[james hobson]

Where is bleeder valve located on a 5.5 an 7.5 evinrude not familiar with this.

[james hobson]

Very true I will check compression any tips on checking would be helpful ,thanks

[crosbyman]

you needa common pressure meter that fits your spark plug holes …

remove the sparkplugs,
install the short hose of the meter
crank the engine over 4-5 times and check compression value
release the air pressure by pressing the purge valve on the meter repeat for second plug hole

compare readings… should be within 10% or so and above 75-80 psi each

utube is your friend…

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• This reply was modified 4 years, 6 months ago by crosbyman.

[lloyd]

Compression test. First of all use a compression gauge that has been reliably used in the past. Perform the test on a motor that is Cold and Dry. Room temperature with no added oil in the cylinders. Warm motor may give false low results. Added oil in cylinders will give false high results. Remove both spark plugs and ground them to the engine block with ignition wires attached to avoid damage to the ignition system. Screw the compression gauge into the top cylinder and crank the recoil until the gauge reads as high as it will go. 3-5 quick pulls should be enough. Write down the comp reading for each pull. If the reading drops between the pulls you have a leak. If so correct the leak and repeat until you get consistent results. Repeat for bottom cylinder and write down the results.

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