Tohatsu 90hp stuck in safe mode, not revving

[jimmy24]

Hi all,
We have a 90hp 2 stroke Tohatsu on a 18' Maxum Speedboat. It's been fine for the last 4 years but now after its last service the engine won't rev or go above 6 knots. We first thought the intake filters might have been blocked but it wasn't that. The engine passes the diagonstic tests, and we changed the cdu which had no effect.
Has anyone got any other sugggestions?
Thanks

[DM]

Originally Posted by jimmy24

Has anyone got any other sugggestions?s

There's a water pressure sensor micro switch on the port side of engine, high up, towards the rear. It can stick putting the engine into limp home mode. Giving it a flick with a stanley blade and a spray of lubricant usually solves the problem.

If the problem persists, you can isolate the switch but Tohatsu don't recommend it for obvious reasons.

It's also adjustable for sensitivity but if you start messing with it, it can take ages to get it right.

[C-NUMB]

Here might be something helping to diagnose the problem:
http://www.rib.net/forum/f37/strange...90a-49600.html

Disconnecting the wires most likely overrides all sensors(oil level, water pressure, water temp....) so You can check is it sensor related or not. But there is also a risks involved running it with safety features disconnected...

[clydeoutboards]

it does sound like a sensor telling it to be in limp home mode but I would be tempted to take it to a local dealer as it should be them taking the risk if you turn off the sensor warnings and not you i.e. they are the experts.

if it was smaller I would say send it to us as we are a bit to far away for even our mobile service!

good luck

[jimmy24]

Thanks all for the comments, some good ideas there for me to try this weekend.
Cheers