![Reply](/forum/images/sk/buttons/reply.gif) |
|
29 March 2024, 23:38
|
#1
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
2 stroke dies occasionally in gear
I have a 50 hp tohatsu 2 stroke 2003 automixing model
When I take it out it will run well for hours but at some point it suddenly stalls. When I start it again it will start fine but it will probably stall again shortly. sometimes the problem goes away. Sometimes when I start it again it will be stuck with low revs like limp mode. Trying more throttle will stall it. This also usually goes away.
Recently I have gotten replaced:
Spark plugs, onboard fuel filter, cleaned carbs, new impeller.
I can’t see any leaks in fuel lines and I have gotten mechanics to take a look at the issue but no luck.
The issue takes hours to happen so It’s hard to test otherwise it runs fine.
I would appreciate any feedback
__________________
|
|
|
30 March 2024, 10:06
|
#2
|
RIBnet admin team
Country: UK - England
Town: Cambridgeshire
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Yam 15 Tohatsu 9.8
Join Date: Nov 2007
Posts: 8,754
|
Hi and welcome to the forum.
Do you mean this only happens when the engine is hot having been run for some time?
__________________
|
|
|
31 March 2024, 09:02
|
#3
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
Quote:
Originally Posted by Fenlander
Hi and welcome to the forum.
Do you mean this only happens when the engine is hot having been run for some time?
|
Pretty much heat. But I have had the boat stuck in low revs like limp mode when it was cold multiple times. But as for the stalling problem it has not done it cold. As far as I know there is a heat alarm and overheating shouldn’t kill the engine either but next time I go out I will try feel the water coming out of the impeller. I just can’t seem to find anyone with the same problem.
__________________
|
|
|
31 March 2024, 11:37
|
#4
|
Member
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: S/R5.4/regal3760
Length: 10m +
Engine: Suzukidf70 2x6lp 315
Join Date: Jul 2009
Posts: 3,918
|
When you say it stalls do you mean it stops as your going along at speed or when manoeuvring at idle speed?
__________________
|
|
|
31 March 2024, 11:45
|
#5
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
Yes in gear and it has happened mostly at a higher speed. It is sudden almost like a kill switch. The engine doesn’t sound any different before it dies.
__________________
|
|
|
31 March 2024, 12:13
|
#6
|
Member
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: S/R5.4/regal3760
Length: 10m +
Engine: Suzukidf70 2x6lp 315
Join Date: Jul 2009
Posts: 3,918
|
I had a similar issue & it was a faulty fuel connector allowing air into the fuel line took ages to find it, maybe worth checkin or even try plumbing direct to the tank to remove the plug in connectors from the system to eliminate them
__________________
|
|
|
31 March 2024, 13:52
|
#7
|
RIBnet admin team
Country: UK - England
Town: Cambridgeshire
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Yam 15 Tohatsu 9.8
Join Date: Nov 2007
Posts: 8,754
|
Like Ken I'd have a forensic look at every part of the fuel feed. But I asked about the time run/heat as sone of my most baffling vehicle issues have been with heat soak intermittent failure of ignition components.
__________________
|
|
|
31 March 2024, 18:09
|
#8
|
Member
Country: UK - Scotland
Town: Near Inverness
Boat name: Hold Fast
Length: no boat
Join Date: Apr 2021
Posts: 85
|
Have the carb float heights been checked ?
__________________
In the Highlands, loving life 👌
|
|
|
31 March 2024, 20:19
|
#9
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
Ah ok. I was told by the mechanic that they were faulty but that once the vacuum started they shouldn’t be an issue. I’ll try eliminating that then.
__________________
|
|
|
31 March 2024, 20:24
|
#10
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
Quote:
Originally Posted by GAVMAC321
Have the carb float heights been checked ?
|
No. I only cleaned the carbs. There was nothing glaringly wrong about the floats but I wasn’t looking. Do you think the issue i described sounds like carb floats? I think I have seen that it could have something to do with the loss of power
__________________
|
|
|
31 March 2024, 20:58
|
#11
|
Member
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 70hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 4,603
|
2-strokes, air, fuel, spark. The last part is a built disingenuous, with HT leads, butterfly valve on air box, etc.
Earlier comment about checking fuel. I had a pattern part Tohatsu fuel connector (engine side) and the ‘o’ ring had dislodged, allowing air to get in. Ensure the connectors are genuine Tohatsu and there’s no air entering. It’s a small thing, but these pattern parts are junk. On the fuel primer bulb, ensure that’s not restricting fuel. Quicksilver are as good as Tohatsu.
When the carbs were cleaned, what were the fuel bowls like. Any discolouration, gunk. How were the carbs cleaned, ultrasonically?
__________________
Is that with or without VAT?
|
|
|
31 March 2024, 21:04
|
#12
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
Quote:
Originally Posted by spartacus
2-strokes, air, fuel, spark. The last part is a built disingenuous, with HT leads, butterfly valve on air box, etc.
Earlier comment about checking fuel. I had a pattern part Tohatsu fuel connector (engine side) and the ‘o’ ring had dislodged, allowing air to get in. Ensure the connectors are genuine Tohatsu and there’s no air entering. It’s a small thing, but these pattern parts are junk. On the fuel primer bulb, ensure that’s not restricting fuel. Quicksilver are as good as Tohatsu.
When the carbs were cleaned, what were the fuel bowls like. Any discolouration, gunk. How were the carbs cleaned, ultrasonically?
|
The carb bowls were very clean. I just sprayed them with carby cleaner and took the valves out to clean as well but I don’t think I ever saw any gunk.
__________________
|
|
|
31 March 2024, 21:48
|
#13
|
Member
Country: USA
Town: NorCal
Boat name: SHARKY
Make: AB
Length: 4m +
Engine: Honda BF75 & BF5
Join Date: Dec 2009
Posts: 2,047
|
Not uncommon for a black box (CDI unit) failure causing loss of spark or limited RPM's. Unfortunately there really isn't much of the way in testing without a lab scope. I went through two black boxes with my old Evinrude 2 stroke 40HP. It would stall and restart but only at a limited RPM. It was too random to test though, so I went with replacement in hopes it would fix it and it did.
__________________
|
|
|
01 April 2024, 08:58
|
#14
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
I tested it again today and I realised that It actually stalls when I use full throttle. It was constantly stalling at about 5000 revs. I have done a bit of research but haven’t found a reason. Does anyone know what this might be?
(It also stalled once in gear and lower Revs as it was cold but that could be a different issue)
I have also replaced the fuel connector which was faulty, that wasn’t it.
__________________
|
|
|
01 April 2024, 09:57
|
#15
|
RIBnet admin team
Country: Ireland
Length: 4m +
Join Date: Feb 2008
Posts: 14,856
|
Are you happy that the 2 stroke automix is working correctly? Hard to know, but you should have some idea of normal consumption. Have you tried running on pre-mix?
On another tack, is sufficient fuel actually being delivered at high revs? Is the bulb on the fuel line hard after the engine stalls?
__________________
.
|
|
|
01 April 2024, 11:56
|
#16
|
Member
Country: UK - England
Town: South Yorks
Boat name: Black Pig
Make: Ribcraft
Length: 5m +
Engine: DF140a
MMSI: 235111389
Join Date: Feb 2008
Posts: 12,101
|
Quote:
Originally Posted by Xgzfutfgut
I tested it again today and I realised that It actually stalls when I use full throttle. It was constantly stalling at about 5000 revs. I have done a bit of research but haven’t found a reason. Does anyone know what this might be?
(It also stalled once in gear and lower Revs as it was cold but that could be a different issue)
I have also replaced the fuel connector which was faulty, that wasn’t it.
|
Is it happy all the way up the rev range to the point where it stalls? Will it accelerate & behave normally below the stall point, or is it reluctant & sluggish?
__________________
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4: Don't feed the troll
|
|
|
01 April 2024, 20:08
|
#17
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
Quote:
Originally Posted by Pikey Dave
Is it happy all the way up the rev range to the point where it stalls? Will it accelerate & behave normally below the stall point, or is it reluctant & sluggish?
|
It is usually fine until you hear it rev louder for just a second then it stalls
__________________
|
|
|
01 April 2024, 20:12
|
#18
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
Quote:
Originally Posted by willk
Are you happy that the 2 stroke automix is working correctly? Hard to know, but you should have some idea of normal consumption. Have you tried running on pre-mix?
On another tack, is sufficient fuel actually being delivered at high revs? Is the bulb on the fuel line hard after the engine stalls?
|
The bulb isn’t hard after stalling but usually when I run it for a bit (and it’s running fine) the bulb will be soft also. What I need to try next is have someone pump it as I stall it
__________________
|
|
|
01 April 2024, 20:14
|
#19
|
Member
Country: Australia
Join Date: Mar 2024
Posts: 10
|
Quote:
Originally Posted by Peter_C
Not uncommon for a black box (CDI unit) failure causing loss of spark or limited RPM's. Unfortunately there really isn't much of the way in testing without a lab scope. I went through two black boxes with my old Evinrude 2 stroke 40HP. It would stall and restart but only at a limited RPM. It was too random to test though, so I went with replacement in hopes it would fix it and it did.
|
Yea I have similar issues to cdi failure but hopefully that isn’t it. It’s the most expensive part
__________________
|
|
|
01 April 2024, 23:09
|
#20
|
Member
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: S/R5.4/regal3760
Length: 10m +
Engine: Suzukidf70 2x6lp 315
Join Date: Jul 2009
Posts: 3,918
|
Quote:
Originally Posted by Xgzfutfgut
It is usually fine until you hear it rev louder for just a second then it stalls
|
Most engines when they run out of fuel pick up the rpm before they die out. This suggests fuel is your issue . I'd be looking for possible points of air ingress or fuel restrictions in the fuel feed system
__________________
|
|
|
![Reply](/forum/images/sk/buttons/reply.gif) |
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|