1987 150 hp outboard

"I am in Harlingen Tx, trying to help a friend. He has a 150 hp Mercury Outboard about a 1987. Motor has not been used very much and has 150 psi compression. The problem is it will come up on plane once. Then rpm drops back to 3000 and will not rev up a again. The motor just flutters. Remove plugs wire and none seen to be dead. All get hot and don't look fouled. Tank has been remove emptied and flushed. Fuel pump repaired. Carburetors removed and cleaned. Nothing was ever found in fuel system.
He then took it to a Mercury dealer and the Dealer replaced the switch box and oil sensor and said it was fixed. The boat did the same thing the next time he put it in the water. On plane once and then flutters. Sounds like it my be running against a rpm limiter. Good water stream out weep hole. Any suggestion would be appreciated."

"You need to confirm whether o

"You need to confirm whether or not it's losing spark when it "flutters".

Easiest way is to check with a timing light while underway and the problem occurs.

If it's losing spark to an entire bank it could be a bad switchbox (you say it was replaced, but there are two on this model - were both changed out?) or idle stablizer module, either of which would have the effect of a "rpm limiter"...."

I made up a bank of 6 spark pl

I made up a bank of 6 spark plugs and attached to engine. All fired good blue spark when engine was cold or hot.

try heating the flywheel up wi

try heating the flywheel up with a hair dryer and see if you loose sparky also

The engine has spark on all ho

The engine has spark on all holes when it has been running for 30 minutes and is warmed up and all plugs are hot to touch. What does the warming of the flywheel with dryer do?

The trigger and stator (bo

The trigger and stator (both under the flywheel) can develop cracks or broken wires in their respective windings (bobbins).

As they heat up (heat from running engine) the copper expands. If their integrity is bad the winding will expand and lose continuity.

The hair dryer/heat gun trick allows you to simulate the condition..

Is there a electrical test tha

Is there a electrical test that can be done to test the stator assy.

YES

you own a multi-meter a

YES

you own a multi-meter and DVA?

I have a data logging fluke an

I have a data logging fluke and a good analog. No DVA

"OK

you can test short to g

"OK

you can test short to grounds

but you want that DVA, trust me, its all volts these days, ask NASA, LOL

http://www.marineengine.com/parts/cdi_electronics/catalog.html?[url]http://www.marine engine.com/parts/cdi_electronics/cdi00056.htm[/url]

funny if you Google it its 55 on here, LOL

are you good with electronics???

$20 can build ya one"

I have ordered the parts and I

I have ordered the parts and I will build a DVA. It turned out to be that the stator was bad. Thanks to all you guys that helped with information.