ex RNLI 30 hp difficult to start and

[toonpirate]

Hi all,
I finally got on the water last Sunday on my SIB powered by an ex RNLI 30hp Mariner 2 stroke bought from a dealer.

The engine took some starting down on the quay and idled not too well and in fact cut out unless you held the throttle open a little.

I rang the dealer up to discuss and ran some through some basic checks on the phone. The dealer then rang back and informed me he had tried to start another outboard of the same make / model and had similar problems to me getting in started.

He changed the spark plugs to non resistive types and said this cured his problem and was sending me out some in the post to change. (The engine sticker states fit resistive plugs). I've done a tinternet search on resistive plugs and I fail to see why they would make starting easier as they apparently just supress radio interference.

Any thoughts please?

[Fenlander]

If your engine is spec'd for resistive plugs then it should start perfectly with them. It's not just radio interference to worry about... non-resistive plugs can give off RFI that will cause false triggering in electronic ign systems so should be used with care in anything other than an old points based outboard.

[toonpirate]

I ll post in the engine section so please feel free to delete

[toonpirate]

Hi all,
I finally got on the water last Sunday on my SIB powered by an ex RNLI 30hp Mariner 2 stroke bought from a dealer.

The engine took some starting down on the quay and idled not too well and in fact cut out unless you held the throttle open a little.

I rang the dealer up to discuss and ran some through some basic checks on the phone. The dealer then rang back and informed me he had tried to start another outboard of the same make / model and had similar problems to me getting in started.

He changed the spark plugs to non resistive types and said this cured his problem and was sending me out some in the post to change. (The engine sticker states fit resistive plugs). I've done a tinternet search on resistive plugs and I fail to see why they would make starting easier as they apparently just supress radio interference.

Any thoughts please?

[willk]

Originally Posted by toonpirate

Any thoughts please?

Yes - it would be hugely helpful if you didn't make duplicate posts

[toonpirate]

Ha, a good point. I can't delete sorry ��

[paulbrown22]

I've got a 1999 Mariner 30 2-stroke that I've owned from new on the back of my Tomkat RIB, very lightly used. It never used to like starting or idling practically from new, always needed some serious use of the electric starter motor to get it going. Finally last year I removed, stripped and cleaned the carb, and ever since it's started just on the pull start after a few pulls. So if nothing else, but be worth checking/cleaning the carb and making sure it's set up correctly.

[toonpirate]

Thanks Paul that's what I was thinking was my next move. Is this a fairly easy job or specialist tools required?

[paulbrown22]

Certainly no specialist tools, I just used my standard socket set, spanners, screwdrivers, etc.

From memory, I had to shift the board with all the electrical connections/fuses on the front starboard side to make room for the spanners on the main nuts, remove the air intake cover, fuel pipe, throttle and choke connections, and I could then undo the carb body from the block. Taking the carb apart was then just a few more spanners and screwdrivers. Make sure you measure where the various needles are before unscrewing them, or find a service manual and reset to the factory settings.

When I then replaced the impeller later on, I ended up taking the carb off again to be able to undo the gear linkage, so I've had it off and on again several times now, and it wasn't that hard at all.

[toonpirate]

Great thank you.

[Eric]

The unused fuel in the carburettor will turn into goo and usually clog up the galleries if engine left unused for some time. Try taking the carb apart and boil them in hot water for 5-10 minutes. Hot water will get into the galleries and break down the goo.

[toonpirate]

Thanks Eric I ll take a look.

[jwalker]

Cleaning the carb is a good starting point.
Getting a good tickover requires fine setting of the mixture screw. When the engine is properly warm, adjust it for maximum revs. If the revs go crazy high, back off the tickover speed adjustment and readjust the mixture. You'll notice the engine revs don't noticeably change over a limited turning of the mixture screw around the max revs point, leave the adjustment on the rich side of that null area (screw outwards) or you may end up with a stall each time you back off the throttle and slow the boat down. The ignition advance also plays a part in good idling but one thing at a time....

The engine should start easily if it's a good one, check the compression if you can.

[toonpirate]

Thanks I do have a compression gauge. I've downloaded the service manual so will use that and the good advice from here. Thanks jwalker

[Stevem]

Originally Posted by toonpirate

Thanks I do have a compression gauge. I've downloaded the service manual so will use that and the good advice from here. Thanks jwalker

Did you get this sorted toonpirate?

Ive got an old tohatsu 25 that can take a bit of starting. Not trying to teach you to suck eggs here but for my 25 the best starting procedure is prime fuel bulb until hard, choke fully out, throttle at start position. I had a fault on mine where i would pull the choke out but it would creep back in without me noticing, simple adjustment cured this.
Good luck and let us know the outcome

[toonpirate]

I am keeping my fingers crossed its sorted. Compression test was fine, I changed the spark plugs and you are right there is definitely a starting technique. I pull out the choke for one pull of the starter, push it back in then it generally starts within a couple of further pulls. It's always the first start of the day that's the most challenging.

I ll keep starting it for the rest of the week. If all OK I ll leave alone. If not its a carb strip down.
Thanks for the interest.