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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3976
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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1988 mercury 135 v6 outboard wont go over 5 mph for the

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1988 mercury 135 v6 outboard wont go over 5 mph for the first half hour then all of a suden it like all the cylinders kick in and ir runs good the rest of the day its done this the last three time i just leave it floored and drive around until it start working
JA: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else the Marine Mechanic should be aware of?
Customer: i have changed the fuel pump

Hello, my name is***** will assist you.

Would you please post the serial number of the engine?

Customer: replied 1 year ago.
i will try and find it when i get home from work but Ive looked 10 times and never have found it before when ordering parts ive been told to look by starter couldnt find it can you tell me were it should thank you

It should be on a small plate on the right side of the swivel tube.

I mainly need to know if this engine number from the carbs, if you can locate then. They will either be on top, or in the left side of the front.

Customer: replied 1 year ago.
Hi Charles, I found found the little plate with a number I hope it is the number you need B278430

Got it thanks. Do you have a multimeter to do some testing? We need to make some electrical tests on the ignition system.

Have you already checked the compression on the engine? If so, what was it?

Customer: replied 1 year ago.
I have a multimeter havent checked compression i will but wont be able till friday im busy today and tomorrow after work

Thats fine, there are no time limits here. The test I need to know, is a cranking test, or the engine can be at idle. Either way, separate the two switch boxes on the engine, leave all wires attached, including the ground wires. Crank or start the engine, I need the AC voltage readings on the Blue and the Blue/white, then the red and the red/white. The black meter lead will need to be grounded to the small screw that is holding the ground wires on.

Compression needs to be over 90 PSI each and all with in 15% of each other.

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