Hi guys,
Just a little bit of a problem Monday when coming home from a day fishing at Moreton.
Coming back was rough so it was a tough trip for the boat and motor with plenty of water getting aboard due to a few of the massive waves we were dealing with.
Finally got back in near the river so I decided to open her up (from about 2500 to 5500) in the river, where it sat at WOT for a minute or two, but then all of a sudden dropped in power which was matched with a beeping from the control box. So I shut her off, wiggled a bit of this and that, and then started it again and the beeping at stopped.
So I then went to get up on the plane and it would just have no power, and soung like it was running on 2-3 Cyls. But then it would go from bogging down to all of a sudden jumping back up to 4cyls and do that on and off. It then eventually would get to WOT where it would sit fine until I would have to get back up onto the plane.
So, things I should note.
- Plenty of oil mixed in to the fuel
- Telltale was always present
- I think its a 93 model Yamaha 115 2 stroke.
Well my first point of call will be to strip and clean the carbs, then plugs and leads. Just hoping its nothing too serious that a simple man like me cant fix.
If anyone has any suggestions on where to look that would be much appreciated.
btw, caught 4 squire and a pike (yuck).
OK, first off, do not start pulling things to bits just yet, you may introduce another fault, so do all the very simple non invasive things first, like a complete seperate tank hose and fuel, remove the plugs and see what they look like, are they all the same? rep[lace them anyway, compression test (just for kicks) do the easy stuff first, then start to look further.
Possibly plugs first? Always worth a try, more than once new plugs have pulled up the necessity to look further, next is drain and basically clean the carb bowls and refit.
From this point onwards it will be more game on, chances can be it will not be needed. 7/10 further pull downs in my experience can be related to just these two things if the truth was known before the wrong plan of attack was made.
Just one cylinder misfiring will pull the entire engine down a long way compared to a 4 stroke.
cheers fnq
Ok sounds good. If I am in the area of plugs, is it worth doing the coils and leads?
Where would be the first place to look at getting parts? Is Yamaha the only place? Because they seem to sting a bit on the pricing.
Any of the japanese outboard places will have NGK and only NGK, forget leads and coils as the initial problem (unless you just want to or it's convenient)unless you want a spare unit (nice to have and for trouble shooting). You will find the leads differ from most other stock and although you can change them out with after market, they are of such low impedance it's hard to find good roll replacements.
It all depends on how much money you want to spend, a person can go at it targeting just the problem or start replacing bits, new is 99% of the time better than old after all.
A good soaking with water displacement spray and a check of all connections can do wonders also, esp as you say it was rough, inducted into the cowling salt water spray can cause shorts that will just go away until next time.
cheers fnq
Yeah I was just thinking more for piece of mind. I would like to nut out the problem first and was just thinking of maybe even getting a full overhaul with new ignition, fuel pump, carbies cleaned and reset, timing etc etc.
But how will I go about nutting out the problem areas without having to fix things then take it out on the water? lol. She idles perfect and yeah, without any load might make it hard which was why I was thinking of just doing a whole lot as its an old motor (pre oil injection days. Any ideas on what year?).
But then again I do use it every weekend and it probably does about 150-200kms (3-4hrs) a weekend, so probably wouldnt hurt to get all of it done.
You can work out the year built by the serial number. For some reason known only to themselves yami worked backwards from somewhere in the alphabet. I've fogotton the details but if you do a google you'll find the numbers.
My 115 did a similiar thing once and the problem ended up being the black box but, as others have said, do the simple things first then buy a manual if you want to do the rest yourself.
Effectively you cannot be sure you found the fix from testing on the muffs or in a drum at home. You do need load hence why it is best to investigate as much of less invasive maintenance like bits first.Originally Posted by mustang5
Do not discount an overheat unless you did physically feel the engines head with your hand.
Bottom line is it up to the owner where they go, if out of enthusiasm the cost/time becomes much greater than they needed to be otherwise..... although the owner is happy, that's good! but it's a less than an ideal place to be replacing lots of stuff in one go as a result, not actually pin pointing the problem.
IMO leave the timing and linkages entirely alone, no good can become of this direction in your instance and at this time.
Full carb work if you feel you must, clean bowls/filters, new fuel (water will cause these symptoms), new plugs, wash/dewater all under cowl areas, then take your chances, (new fuel pump is always a good precautionary investment if the old one has a good few yards on it) with luck and most of the time it will be all that's needed, 2 strokes are pretty simple beasts.
cheers fnq
Alright I see where your coming from, good point mate!
I will do the simple things first, plugs, drain the fuel (80 litres in the tank
Just took another quick look and the rough ride home seemed to have loosened the battery terminals, and the bracket for the battery (350hp rated century) was snapped.
With regards to the overheat well it was probably the hardest work for the trip home that I have had to do with this boat (about an hour accellerating in and out of swell 25knt), so maybe given that and the amount of weight I had on board that could have had an affect.
Also the amount of Bow waves we took which came over the windscreen well, who knows where that salt water ended up? .
Cheers again for the help guys. Will advise what it ended up being as soon as I figure it out.
I would not go replacing too much without a little more troubleshooting . There have been previous threads here about similar events with the Yammie 115 2 stroke . You said the buzzer was going off . Did it also go off all the other times when you lost power ? . This is the key to your troubleshooting here .This engine and others have an overheat protection which sounds the buzzer and cuts ignition to two cylinders to limit further overheating until it gets below the temp switch setting again when all is good usually until you use higher RPM again . Usually only shows as a wide open throttle problem at first then gets more frequent . Engine runs normally at lower RPM's .
From my memory can be caused by one of the the switches ( less likely ) and from salt crust build up in the narrow water gallery in the top of the head ( both have their own switch ) . The fix for this is head removal and cleaning . Not a huge or mega expensive job on a two stroke . This is assuming no probs with the water impellor . It all hinges on the buzzer sounding or not .
Chris
Hi mate thanks for the reply. The buzzer only sounded the initial time when it shut down from WOT to lower revs. After turning it off and back on again, the buzzer was still on. Then turning it off and on again instantly after that the buzzer was then off. But even with buzzer off, it was intermittently cutting in and out of full cyls/2 cyls. But did get back up to WOT and stay there but the trip to WOT was extremely slow lol.
Cheers
Check for corrossion on wiring to oil resevior pump, if this is faulty oil may not be pumped accross to the motors resevior each and every time it is called for by the low level indicator float sensor.This will cause the alarm to go off and limp home mode to kick in on the motor. Sometimes its hard to catch out , if its a intermittate connection problem . Next time it alarms check the oil sender resevior level under the cowl - if its low - and the oil pump is not running or runs on / off this may well be your problem. Your gauge should also show you when the sender oil vesell is running down and then being topped up as a series of bars across the bottom of the gauge , You wont have to do anything to run this test just observe the workings, of the float level which sends the signal to the oil pump.The oil pump will top up the sender resevior when the ignition is on,you will just need oil to be called for , motor does not need to be running for the oil pump to run - if you listen carefully you will hear the pump purring when oil is being transfered across to the engine, it should be continous until the sender reaches high level. If the pump either doesnt kick in or run continuously you may simply have a bit of corrossion on the wiring to your oil pump .
PS , there is a switch on your oil sender resevior , to manually activate the oil pump - this is the easiest way of testing the oil pump but you have to touch rather than observe).
Alarms usually go off for heat, lack off oil , or over revving, I'll be interested in what you find.
BeastMaster
Keep Ya Tip UP
Beast
Hey guys,
Well after doing the impeller (half hour job, and $50 for parts), checking compression and replacing and cleaning all filters and fuel lines, then taking it on the water I was a little upset to see that from the word go she was only running on 3 cyls.
So I had a set of brand new spark plugs that I was starting to replace at the pontoon (last night lol. So much easier than leaning over the back). As I was replacing, I quickly realised that the whole problem all along was that the ignition lead to the cyl 2 coil had come out of its end cap which goes onto the spark plug.
A quick electrical fix and a test run delighted me to have her running better than ever.
Then due to my eagerness, well instead of darting around in the river, we headed to Mud island to make good use of the 5knt winds. Sat on 400-5000rpm for a good 30 to 40 minutes without skipping a beat.
All in all I can sit back and know now that a large chunk of the motor components are now like new.
Another thing is, if you are ever going to change your impeller at home, make sure you look at the next link. I did and it was a godsend!!
http://www.thehulltruth.com/shipyard...ment-f115.html
Thanks again all!
All's good that ends good and it got a partial service, 5kn winds! what's that?!
cheers fnq
I think that's what I said on the very first reply to your question, do all the easy checks first, do not throw a bag of parts at it first, you will be very surprised (well probably not now) how many faults are simple, but if you start pulling things to bits, you can introduce a new fault and then have two to find.
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