Yam 115 four stroke problem

[Johnscubanut]

Hi guys, our people have been out today diving from our rib. They have just reported that the engine dropped down the revs & the red light came on indicating a problem, and the engine automaticly reduced revs.
I'm told it was on the gauge where the fuel meter is situated, although it was not a fuel problem. Overheating was my first thought? Blocked water inlet possibly?. They checked, but all ok. But also they said when they tried to trim up or down the power dropped again only achieving around 4500 rpm. They limped back at reduced speed & the engine is peeing water fine on the flushing muffs.
This engine revs out around 6000. First time of this fault
I'm thinking an electrical problem connected with tilt/trim?
Any ideas??? Thanks-John

[jyasaki]

Overheating would have been my first thought as well. Pretty easily checked by the telltale.

I'd guess it's more likely a problem with a power connection somewhere. Tilt/trim is a pretty hefty motor, may be dragging down the voltage if it's not boosted by the battery.

Is your charging system working OK?

jky

[Johnscubanut]

Thanks jky, its a good battery but I'll check the charging system

[BettySwallocks]

I had a similar issue with the same engine as yourself. I also had the warning buzzer come on at the same time. I'm not to sure about the location of the warning lamp.

What seemed to be the problem with mine was low oil level (around quarter full on the dipstick), how it got that low is another story.

I topped up the oil level and the next time out the engine ran faultlessly.

[jyasaki]

Was it the oil level causing the limp-home, or overheating due to lack of oil? Probably need a computer to read the codes, I know, just wondering if you happened to know.

I should clarify my post: a malfunction in the tilt/trim system will not cause the motor to go into limp-home; it needs to be something that is potentially dangerous to the motor. As far as I know (and this is after a perusal of the owners manual), it boils down to 2 things: temperature and oil pressure. If the gauge was a Yamaha gauge, it should have shown which caused the rev reduction (on my 2005, the fault is shown by a LCD bar under the icon - thermometer for temp, or oil can for oil pressure.)

Not sure, but I don't think there is a low voltage alarm on the motor (electronics just quit at some threshold voltage), and in any case, I doubt that would trigger a limp-home, as that would reduce the motor's output voltage even further. Just a thought.


jky