Johno/Suzi 90 4stroke complaining

[Sheik]

90 hp Johnson (suzi)with many hours work - oil light is blinking and warning buzz sounds on low revs for about ten seconds. Once the boat is underway theres no problem but at low revs i'ts rough and doesn't idle well. The water pump is working but occasionally it seems a little interrupted in its stream. Maybe its prostate is playing up. Have read that when it's due for a service the oil light will come on but that doesn't explain the rough idle. Oil level is fine on the dipstick. I'm sure the impeller is buggered but thought it would show up in other ways not oil light. Any thoughts on what I might have to do? thanks ey
jim

[Noelm]

OK, first off, the service reminder beep remains on regardless of speed or how much oil is showing on the dipstick, rough idle COULD be the IAC (idle air control) pretty easy to replace, probably best to get the water pump fixed before you go any further, and check the poppit valve as well.

[Sheik]

Thanks Noel
I'm getting the mechanic to look at it soon but he wasn't willing to say what he thought it was, so I don't like my chances. I'm thinking it might be a BIG problem. Here's hoping its not. I just wanted some ideas of what it might be so I can ready myself and maybe be prepared to ask old mate some relevant questions. Thanks again

[Sheik]

No other thoughts? If I know a little more when I take it in tomorrow morning I can be prepared. I'm
wondering what I will ifn it's a big problem. How much can I afford to spend? Do I have to sell the boat? Well,
we've all been there haven't we.

[Fed]

I'd get him to address the oil problem first, what I mean is you don't want him to replace the impeller and fix the rough idling only to have him turn around & tell you the bearings are rooted.

[Sheik]

I'd get him to address the oil problem first, what I mean is you don't want him to replace the impeller and fix the rough idling only to have him turn around & tell you the bearings are rooted.
Yeah good point Fed. I'm wondering whether the oil problem could possibly be related to poor cooling or is the oil light only going to come on when there's low or high oil pressure. The reason I ask is that the problem sounds a little like a poppit valve stuck open, which leads to rough idling but no problems when the revs are up.
Does that sounds possible to the petrol head motorfaces that read this forum?
thanks.

[Moonlighter]

Could be anything, as simple as a bad plug lead or a clogged injector or two, or as complex as anything. Not much point speculating, let them hook up the Suzuki diagnostic computer to it and it will show diagnostic codes and allow them to test various things to help diagnose the problem and find a solution/s

You are using a mechanic that has access to that technology and knows how to use it, arent you??!!

[Sheik]

I sure hope so.

[Mupster]

Sheik what ended up being the problem?

[Sheik]

there was a problem with the casing. old mate had left it in the canal and the housing had corroded so the mechanic got a bloke cut out a section around 50 x 100mm and welded it back. no problems since. going like a train. except quieter.

[Noelm]

The fault description does not sound like that fault....the corrosion issue is very common, and bugger all to do with leaving it in a canal! A better fault description, or even the light flashing sequence would have got lots of response.

[Sheik]

The fault description does not sound like that fault....the corrosion issue is very common, and bugger all to do with leaving it in a canal! A better fault description, or even the light flashing sequence would have got lots of response.
Sorry Noelm, I'm not sure what you mean there. Perhaps my description of the problem is off the mark, which could be the case given my tiny knowledge of outboards.

[Noelm]

Not having a go at you, just kind of saying that it's hard to fix a motor when it's right in front of you, let alone trying to help via a keyboard, so, precise descriptions of what's going on "might" provide different answers.