opti 1100 hrs

Falcon · 18 August 2005, 21:01

I have looked at all the previous threads on this but wondered if anybody had anything new. 150 opti 1100 hours well serviced and just seviced with all main parts changed including two new thermostates, new injectors last Aug. The engine is cutting out on tick over and the revs are fluctuating between 480 and 620, cuts out when dips to 480. It has been plugged in and tested but nothing found, mechanic has tested and checked all he can and is stumped. I have disconected, cleaned, and wd40'd everything and checked all oil system. Any ideas???

Turbodiesel · 19 August 2005, 07:25

The DDT plug in machine is ok, but you need to get the fuel and air pressures checked too.

hard1 · 19 August 2005, 11:35

1100 hours on an Opti! Well done. I thought I was doing well with 750!! Sorry, can't answer your question - good luck anyway.

Manos · 19 August 2005, 12:12

Electrics I think.
In idle the revs go up and down and the engine cuts out at the end. It does not hold idle speed.The engine works OK while accelerating and in gear. A friend with the same engine had exactly this problem problem.
May be is Electrics then.

LURCHER · 20 August 2005, 06:54

I too have a 150 and notice that when trimming up or down the revs drop a little so I assume that the trim motor is taking some of the electrical power away from the injectors , this only happens at low revs . Maybe your battery is tired or the alternator is not doing it stuff well enough . New alternators are £420 I know I have just fitted one !

Falcon · 20 August 2005, 21:03

Thanks for all your help, i will get the pressures checked. The batteries are new start of the season, the alternator has been checked and is okay. I have read on the web of somebody with the same problem putting a fuel additive in the filters to clean the fuel system, has anybody heard of that on an outboard before?

Manos · 20 August 2005, 22:27

I am just talking to my friend and he says that most likely is the sensor on the motor. Check this also

Richard B · 20 August 2005, 22:59

Quote:

Originally Posted by Manos

most likely is the sensor on the motor.

Very illuminating, Manos. I suppose it's a bit more specific than "May be is Electrics then"

. I wonder how many "sensors" there are on an Optimax?

Manos · 21 August 2005, 08:25

Sorry

about that Richard but my knowledge of the OPTIMAX's in and outs in bellow Zero and as far as electrics are concertned I know

all about it.

I am just trying to help

As I said this friend of mine has exactly the same engine as Falcon does and HAD exactly the same problem while he was on holidays in Greece.

Now he went back home he checked this problem and he also put the engine on the computer which also did not show that anything was wrong with the motor.

He said to me though last night (when we were chating on Skype) that his engineer told him (after a few days) that it was the sensor. How many and what sensors they are on an Optimxa I haven't got a clue (I ONLY play with Yamahas

). I assumed that it would be one (if he said that ti was THE sensor)

Still he hasn't got back the boat from the engineers. When he gets it back I have asked him to tell me exactly what they changed and what they repaired ........ and then I will be more specific

Rogue Wave · 21 August 2005, 08:33

The problem somebody mentiones about trim ing affecting the revs is caused by the power feeds (big cables) not being man enough to carry enough current to satisfy the engine, or the ends becoming corroded. Or some tosser putting a join in the cable feeds.

Are you getting any messages on the smartcrafts re Data bus error

Daniel · 21 August 2005, 10:20

There is a flywheel sensor which sends the timing info. back to the ECU and it's prone to dirt and/or moving very. very slightly which can cause all maner of problems, including starting and running. I would check and clean this, although i would imagine (a) the DDT would highlight this and (b) an optimax trained mechanic would know about this but it's worth a look.

From memory (boat in marina) it's located on the port side of the engine near the top of the bug air-whotsit.

Manos · 21 August 2005, 15:09

................. and Richard saw the light

Seriously good info for Falcon though

Turbodiesel · 21 August 2005, 19:27

The DDT is pretty good at picking up sensor failures. Dont think thats going to be the problem. Low batteries or alternator problems will show up on your tacho when your running the engine or when you start it. Check the fuel and air pressures.

codprawn · 22 August 2005, 00:56

Not a clue on the opti but have seen similar problems on various other engines - caused by air leaking into the plenum chamber - also could be a dirty air valve pot. Don't even know if optis are setup like this but if they are worth a look. Sometimes things like this could be as simple as a small hole in a rubber bellows etc.