Sputtering

[Todd027]

I have a 94 yamaha outboard 115hp 2 stroke. It will run for about 2-3 minutes great. Then goes into almost limp mode sputtering.. have checked fuel filter, ran it until it sputtered then tried pumping ball it was hard couldn't pump. Not sure if it could be a fuel pump or something different. Checked fuel have 1/4 tank.

 

[Todd027]

Here's an example

 

[CaptnKingfisher]

I've never worked on a Yamaha and I've never seen this symptom before so I'm probably not qualified to give advice on this. But to me it sounds like your losing spark on 2 cylinders. Will it do this in the driveway on muffs at idle? That would be nice cuz then we can do some troubleshooting while the symptom is present. Gonna look for a manual so i get familiar with your ignition circuit

 

[Todd027]

No it only does it while on the water. In the driveway at idle runs great. Only does it after open throttle for like 2-3 minutes. Not hard to start. And has not stalled out because of it

 

[Todd027]

I've never worked on a Yamaha and I've never seen this symptom before so I'm probably not qualified to give advice on this. But to me it sounds like your losing spark on 2 cylinders. Will it do this in the driveway on muffs at idle? That would be nice cuz then we can do some troubleshooting while the symptom is present. Gonna look for a manual so i get familiar with your

I've never worked on a Yamaha and I've never seen this symptom before so I'm probably not qualified to give advice on this. But to me it sounds like your losing spark on 2 cylinders. Will it do this in the driveway on muffs at idle? That would be nice cuz then we can do some troubleshooting while the symptom is present. Gonna look for a manual so i get familiar with your ignition circuit

No it only does it while on the water. In the driveway at idle runs great. Only does it after open throttle for like 2-3 minutes. Not hard to start. And has not stalled out because of it

 

[Todd027]

Did compression test all cylinders 120.

 

[99yam40]

do you have gauges that will show warning lights and a working alarm system you can see and hear if the motor overheats or is low on oil?

what RPM is the problem showing you at?

I would guess at this point the motor will not go above 2000 RPM when it overheats after a few minutes of running

 

[Todd027]

do you have gauges that will show warning lights and a working alarm system you can see and hear if the motor overheats or is low on oil?

what RPM is the problem showing you at?

I would guess at this point the motor will not go above 2000 RPM when it overheats after a few minutes of running

No alarms are going off. And runs great around 3000 rpm for a short time then drops to under 2000. And it's a 2 stroke so gas and oil mixture.

 

[Todd027]

do you have gauges that will show warning lights and a working alarm system you can see and hear if the motor overheats or is low on oil?

what RPM is the problem showing you at?

I would guess at this point the motor will not go above 2000 RPM when it overheats after a few minutes of running

Sorry finger hit wrong button 5000 rpms for about 2-3 minutes then drops to 2300.

 

[99yam40]

sounds like over heating

are you sure your alarm system is working properly

 

[Faztbullet]

Looks from video its going into limiting mode either from overheat or bad pack or possibly low oil sensor depend on model number of engine

 

[Todd027]

Looks from video its going into limiting mode either from overheat or bad pack or possibly low oil sensor depend on model number of engine

Ok great I will go through my water system this weekend and change things out . It's about time anyway. I usually do it winter time. But can't go out with it like this so might as well go through it. Thank you so much for your help. How would I check the coil packs to know what one is bad?

 

[99yam40]

if it s an overheat, you need to fix the alarm system.
if the alarm system is functioning properly then I would not think you need to chase the over heat.

test the system to see

 

[Todd027]

if it s an overheat, you need to fix the alarm system.
if the alarm system is functioning properly then I would not think you need to chase the over heat.

test the system to see

Yea I believe your right I'm going to go through the whole system this up coming weekend. I'll let you all know what I find to possibly help out someone else with the same problem. Thank you all for your help and direction to go