Suzuki woes and dolphins

[Erin]

Had a fantastic day out on the water today and saw a small pod of dolphins just off Les Ecrehoes. They followed the boat for a bit, but were a bit camera shy unfortunately.

However, more to the point, having praised my Suzuki to numerous people in recent months, it has developed an annoying habit of overheating. The rev limiter will cut in and drop the revs and the tell tale looses pressure. As soon as I throttle back it recovers and is fine to accelerate again. This happened twice today,once on the way out at about 5,000rpm, and again later at about 4,000 rpm. It seems to be after say 30 mins of running, but instantly resolves itself. It's a 2003 DF90.

Secondly, and not necessarily related, I noticed the fuel primer bulb had been sucked in to within an inch of its life. Engine was running fine, so I assume there must be a restriction further back in the fuel line.

Any thoughts??

Keith

[AndrewH]

Erin

Probably like teaching granny to suck eggs but I have to ask whether you've checked the obvious first ...

Have you checked to see whether there is some obstruction (weed etc) blocking the water inlet? This would clearly cause both an overheat and a loss of telltale pressure. Its also possible that when you throttle back, there is less "suck" on the inlet, so that the obstruction can move a little and thereby allow more water through .. Engine then cools ... and you are back to normal

Good luck with the fault finding

Andrew

PS Cool dolphins by the way

[Aidan]

Ok I asume that you have air replacing used fuel? failing that, try pulling the bits of Dolphin chum out of the water inlet

[codprawn]

Check your intakes and remove the plate - could be something trapped behind it. I had exactly the same problem with my Suzuki 15hp 4 stroke. It turned out there was a piece of black tape stuck over the intake which was flapping about!!!

As to the fuel remove the fuel tank cap and see if that cures the problem - if so it's just the breathers.

[DM]

Originally Posted by Erin

and not necessarily related

I think it is related. If you've got a partial blockage and fuel pressure is reduced, that could be causing your overheat problem.

[codprawn]

Originally Posted by davidmanning

I think it is related. If you've got a partial blockage and fuel pressure is reduced, that could be causing your overheat problem.

True it could be causing the engine to run too lean.

[Erin]

Well, I've solved one problem. I found some crud in the fuel line which had made its way from the tank up to the barbed fitting on the fuel filter where it had got jammed in place because of the reduced bore. It was so tightly packed it's a wonder any fuel got through at all. That's one powerful fuel pump on the engine. It seems to be flakes of fibreglass that have got in. I know I was scrupulously clean when I changed the plate on the top of my tank a couble of months ago, but it either wasn't good enough or the bits had been lingering in there from construction.

I have my doubts now that the overheating has anything to do with fuel supply problems, so I'm still looking for probs. I have tested the thermostat in hot water with a thermometer and all is correct. I've also disconnected as many tubes as I can around the block and blown through them, and again I can't find any sign of blockage. Strange one, as it's only a temporary blip and only happens after about 30 mins of journey. Happened once last season, on only one of my outings, but this season it's happened twice in one trip.

Cheers
Keith

PS the first thing I did was undo the fuel filler cap to check there was no breather problem.