1988 100hp mercury spark plugs

[flyingscott]

That is absolutely a diaphragm pump. Clearly shows them in the pic 5 and 2. If it gets its pulse from block pull that hose off and see if it's full of fuel. It should not be

 

[Texasmark]

I bought a new '88 115 in the first quarter of '89. I had that engine for 10 years and only thing I changed was the water jacket cover that encircles the plugs at the rear of the engine....piece of cake. Plugs were NGK BUZHW (NLA) surface gaps and I never had a reason to change them. I had them on a Ranger pad hull and fished alone with top speed 50 give or take and RPMs, at best trim performance position, 6 k RPM. Sweet boat. At that setting I could hear the engine singing and the prop blades beating the surface of the water......prop was an original issue Mercury SS Laser pitch 19 or 21, forget which.

 

[flyingscott]

l76v champion should work.

Mercury - NGK Outboard Motor Spark Plug Guide

www.marineengine.com

 

[Dave1027]

No it doesnt. There are accelerator pumps on the bottom 2 carbs that can leak.

The accelerator pump is completely different than the enrichner. Also this motor's accelerator pump is not a part of the carburetors. It's a separate diaphragm that is throttle linkage actuated and plumbed to the bottom two cylinders.

 

[flyingscott]

The accelerator pump is completely different than the enrichner. Also this motor's accelerator pump is not a part of the carburetors. It's a separate diaphragm that is throttle linkage actuated and plumbed to the bottom two cylinders.

edit

 

[flyingscott]

The accelerator pump is completely different than the enrichner. Also this motor's accelerator pump is not a part of the carburetors. It's a separate diaphragm that is throttle linkage actuated and plumbed to the bottom two cylinders.

You're the expert help hin with his motor then.

 

[scotty8882003]

The accelerator pump is completely different than the enrichner. Also this motor's accelerator pump is not a part of the carburetors. It's a separate diaphragm that is throttle linkage actuated and plumbed to the bottom two cylinders.

Is there a filter on the accelerator pump? I can’t seem to see it. Unless it’s tucked in with the carbs hidden maybe

 

[Chris1956]

Gee, Scotty, did you check the fuel pump diagram for leakage? That would be my first check.

 

[Dave1027]

Is there a filter on the accelerator pump? I can’t seem to see it. Unless it’s tucked in with the carbs hidden maybe

Yes. There is a small filter on the accelerator pump output. It's on fuel line going from the pump to line that connects to the #3 and #4 cylinder check valves. But there should not be an issue with that filter. Not much can go wrong and the amount of fuel going through it is minimal. I'd look elsewhere.