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Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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My Yamaha 70 presion blend outboard motor normally runs at

Customer Question

my Yamaha 70 presion blend outboard motor normally runs at 4500 rpm at full speed.
I checked it out in my driveway before my last trip (just to be sure it would start) and when I put it in the water later it would only run up to 2200 rpm
What happened and how can I fix it.
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.
Hello my name is ***** ***** am I speaking with?
I have some questions back to you.
1. What is the model number on the engine?
2. How old is the fuel in the tank?
3. When was the last time it made full power under a load?
4. The engine will require troubleshooting and the basic start with compression and spark testing, both of which require some tooling. Are you able to do those tests/have those tools?
Customer: replied 2 years ago.
The engine worked well on may 18th 4500 rpm at local lake. I trailed it home and did nothing until May 25th . I tested it out in the driveway (using my garden hose as usual) just to be sure that all was well. I did not run it up at this time. When I got to the new lake, the best it would do was 2200 rpm under the same load as before. The engine will turn up to 4500 rpm when out of gear. I have not added gasoline
Customer: replied 2 years ago.
What ever happened must have happened when I tested it in the driveway.
Expert:  Jason replied 2 years ago.
The engine needs to be spark tested in order to determine if it is firing on all cylinders. This can be done with either a timing light, or an adjustable gap spark tester. Is this something you can do?
Customer: replied 2 years ago.
Yes I can do this and I will start right now
Expert:  Jason replied 2 years ago.
Okay let me know what you find.
Expert:  Jason replied 2 years ago.
Just checking in. Any luck?
Customer: replied 2 years ago.
I installed new sparkplugs and with the motor running disconnected and replaced each plug but could tell little difference in the sound of the motor. This may be beyond my expertise.
Expert:  Charles replied 2 years ago.
Hello, my name is***** you for allowing me to assist you today.
Do you still need assistance on the engine?