Optimax starting problems

[ktnv]

Hi,
I have a 150 opti which i have great trouble starting from cold. I have read here that they are very sensitive to voltage/current, however once the engine has fired once, it will be absolutely fine all day.
When starting for the first time, it cranks over very slowly, and gradualy gets faster and faster. After three or four 10 second attempts you can hear it cranking faster until it suddenly goes. If you then switch off and have another go it starts instantly. I am wondering if it could be the folllowing:

Battery cables - i know that these are not in great shape on mine - but why the increase in cranking speed?

starter motor - could this be slightly seized?


if anyone has any thoughts please let me know!

many thanks

james

[PeterM]

HI James I had exactly the same on my 200. When a decent electician looked at it the voltage was actually 5v at the motor ( despite showing 12 on the gauge) under the load of trying to turnit over & spark at the same time.

I'd definately put money on the cables if you are aware they are not great. I changed mine at the start of this year having got to the stage where it may or may not go at the end of last year. I stuck new batteries & switches in it to for good measure.

Since then it has started within seconds of turning the key. I subsequently realised that before I got the boat the bilge pump had packed up , it had filled with water, dunked the cable ends & they were over the course of 6 months corroding inside the outer plastic.

On cutting back the insulation you could see them happily going green ! Hopefully a simple replacement job for you .

I'd be hesitant about the starter as it sounds like its doing its job OK - but I am no expert - just had experiance of the same thing.

Three or four attempts for 10 secs I am sure seems like a long long time ! It was for me .........

[ktnv]

thanks for that, it certainly seems like the most likely explanation, i just can't work out why it only does it on the first start of the day.

james

[jambo]

Hi I am with Blackroady on this. I had same trouble with my Mariner and it was crroded cables in the truncking. Hope this helps.

J

[PeterM]

Originally Posted by ktnv

thanks for that, it certainly seems like the most likely explanation, i just can't work out why it only does it on the first start of the day.

james

No idea - mine was the same - if it went once it was fine for the rest of the day - I put it down to the battery being cold overnight , the motor needing more power to crank when cold , and once the engine was running it put the batteries back up to 100% charge .

[Chris]

Originally Posted by ktnv

thanks for that, it certainly seems like the most likely explanation, i just can't work out why it only does it on the first start of the day.

james

When the engine is cold it will be harder to turn over, as you crank the crap out of it it will gradually free up. The reason it does not fire initially is becuase there is not enough voltage getting to the injectors. Once the engine loosens up and becomes easier to crank you are then getting the voltage increase to the injectors which allows them to fire.

Either way you want to get it this sorted as your starter will be suffering.

[ktnv]

thanks guys, looks like i will be buying a load of new cable! i have read that welding cable works well, what sort of thickness (amp rating) would i need??


james

[matt h]

i used 25 mm welding cable on my 115 opti, 20ft worked out at £35:from wellingtons welding supplies in Avonmouth, Bristol. thumbs: