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Kohler 7.5R crank, but no start

Posted: October 29th, 2023, 9:46 am
by VicB
Kohler 7.5r. Anchored out Friday night. Took cover off grill for dinner and Venturi tube fell in river (determined this was sort of our theme for the weekend). Plan B cook chicken in skillet on stove. Ran generator for 30-45 minutes, all was perfect. Shut it down for about 30 minutes. Wife said she needed power for galley clean up. Went to start it up and it cranks great but no start. Never had any problems with the gen in the 5 years we’ve owned the boat. Eventually could get a somewhat start. Ran slow for 5 or 10 seconds and died. Never came up to speed. Swapped tanks no change. Remove float bowl on carburetor and it was full. That’s as far as I got. Will get serious about troubleshooting next weeekend. My first part of troubleshooting is always ask if anybody has had this happen? The crank sounded funny, couple of revolutions normal then a higher pitch. Not ready to say that’s a “thing” yet. First thoughts are spark or nasty carb. Boat is 1988 3807. Assume generator is same year. Have no maintenance history. All thoughts will be appreciated!!!!
Vic

Re: Kohler 7.5R crank, but no start

Posted: November 8th, 2023, 1:16 pm
by ColRon
Vic, please see below. This comes from the troubleshooting section of the Kohler 7.5R Service Manual. Hopefully this will get you started on locating the problem. From what you described above, I would tend to look at the ignition side of things and first determine if I was getting spark.

B. Unit cranks but will not start.
1. No fuel.
2. No spark (Section 11).
3. Open foil, loose or broken pin on circuit board (Section 5).
4. Open or ground in harness assembly (Section 5).
5. Faulty circuit board (Section 5).
6. Faulty "1CR" relay (Section 5).
7. Poor compression (Engine Manual, ES-652).
8. Valve problems (Engine Manual, ES-652).

G. Unit Lacks Power
1. Improper fuel (Section 1).
2. Fuel mixture wrong (Section 9).
3. Poor ignition (Section 11).
4. Improper cooling (Section 10).
5. Poor compression (Engine Manual, ES-652).
6. Valve problems (Engine Manual, ES-652) .
7. Carbon build-up (Engine Manual, ES-652) .
8. Set overloaded (Section 1).