Mariner 150 Optimax Problem HELP!!

quietsparrow · 12 July 2013, 15:07

We have a Mariner 150 Optimax that's giving us a bit of grief.

We just cant seam to understand whats wrong with it. Put the computer on and no faults are registering.

The engine did have a overheating problem but after changing the thermostats and the impeller the cooling issue seams to have resolved itself.
Also we have put a new cranking battery on her as the old one was a leisure battery.

Symptoms now are when shes started everything is ok. Runs sweet as a nut. Had her running for about 45 mins and turned her off to do a spot of fishing. Started her up again went along nicely until revs dropped to 3000 rpm and wont go over.

can anyone help??

bedajim · 12 July 2013, 15:12

Quote:

Originally Posted by quietsparrow

We have a Mariner 150 Optimax that's giving us a bit of grief.

We just cant seam to understand whats wrong with it. Put the computer on and no faults are registering.

The engine did have a overheating problem but after changing the thermostats and the impeller the cooling issue seams to have resolved itself.
Also we have put a new cranking battery on her as the old one was a leisure battery.

Symptoms now are when shes started everything is ok. Runs sweet as a nut. Had her running for about 45 mins and turned her off to do a spot of fishing. Started her up again went along nicely until revs dropped to 3000 rpm and wont go over.

can anyone help??

Sounds like safe mode

quietsparrow · 12 July 2013, 15:25

Yeah the computer says its not in guardian mode.

jambo · 12 July 2013, 15:59

Could be fuel. Check primer and also I had similar years ago was diaphragm so maybe check that also the kit ant expensive and easy to change if your handy.

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PeterM · 12 July 2013, 16:03

Had similar on my 200 twice (once in hot weather and once in Sub zero temps) . I'd suggest a fueling issue . I sorted by swapping the main inline filter and primer bulb and pipe between the two.

Jizm · 12 July 2013, 16:46

Note: there are 3 fuel pumps, mechanical lift pump then an electrical low pressure and then the high pressure pump in the vapor chamber..

Searider · 12 July 2013, 17:33

Fault with the neutral position switch in the throttle?
Engine speed is limited in neutral.

Pikey Dave · 12 July 2013, 19:53

Could be crud blocking the pickup in the fuel tank. Are you running portable or under deck tanks?

HUMBER P4VWL · 12 July 2013, 20:18

Quote:

Originally Posted by Searider

Fault with the neutral position switch in the throttle?
Engine speed is limited in neutral.

Throttle sensor? We had similar, intermittent problem of only getting to low ish revs

Jizm · 12 July 2013, 21:29

Quote:

Originally Posted by HUMBER P4VWL

Throttle sensor? We had similar, intermittent problem of only getting to low ish revs

Good shout. That's a possible one, had a fault on that before.

quietsparrow · 13 July 2013, 11:19

Thanks all for getting back to me. I feel like towing the thing out to sea at the moment and pulling the bung out lol.

Were running internal tanks. Had a look at it after lifting the floor and everything looks clean. Ive been told it could be a voltage problem. The fuse on top of the engine that can blow if the batteries are connected the wrong way, while shes running shes only throwing 12.2 Volts and then bumps up to 13.8-14.2 volts while under power. Also she sounds super sluggish and slow while on tick over. Also been told it could be the battery cables breaking down.

Jizm · 13 July 2013, 12:31

Opti's require a tip top battery to run properly. Should be about 13.5v when at tickover. 12.6v with the motor off.

redthunder · 13 July 2013, 18:00

Quote:

Originally Posted by Searider

Fault with the neutral position switch in the throttle?
Engine speed is limited in neutral.

I agree this happened to a mates opti.

Turbodiesel · 13 July 2013, 20:52

Quote:

Originally Posted by Searider

Fault with the neutral position switch in the throttle?
Engine speed is limited in neutral.

If it does this the overspeed alarm will go off and will record as overspeed in neutral. Also it limits the RPM to 4000.
Get a separate fuel tank plugged into it. Also you really need to plug in a fuel/air pressure gauge to check both of those. The CDS will only really pick up electrical faults from its sender it wont look at mechanical faults like fuel and air etc.

quietsparrow · 15 July 2013, 10:25

Thanks guys. Im gonna be heading down to the boat today and have a go at a few things.

Graham pollard · 15 July 2013, 20:43

hi had same prob it was ht leed not in the coil pack properly all good now