cutting out at full throttle

[ahenderson50]

Ok, I'm still working on the 89' 25hp Evinrude that I bought a couple weeks ago. The previous owner told me that it was cutting in and out and needed the carb rebuilt. So I did. Now I've got it running fine up to about 1/2 throttle. But when you open it up it sounds like someone reving up a chainsaw. It is very fast and consistant. When you let off it continues to run fine. I assume this is the problem that he was having with it before. Any ideas?

 

[bktheking]

Re: cutting out at full throttle

Ok, I'm still working on the 89' 25hp Evinrude that I bought a couple weeks ago. The previous owner told me that it was cutting in and out and needed the carb rebuilt. So I did. Now I've got it running fine up to about 1/2 throttle. But when you open it up it sounds like someone reving up a chainsaw. It is very fast and consistant. When you let off it continues to run fine. I assume this is the problem that he was having with it before. Any ideas?

So it runs fine, revs up, goes to 1/2 throttle then it revs higher but you don't go faster? Spun propeller hub perhaps?

 

[ahenderson50]

Re: cutting out at full throttle

No, I haven't had it in the water yet, just muffs. Instead of consistantly reving up to full throttle, when it gets over half it revs up and down really fast then goes back to consistent below 1/2 throttle.

 

[bktheking]

Re: cutting out at full throttle

No, I haven't had it in the water yet, just muffs. Instead of consistantly reving up to full throttle, when it gets over half it revs up and down really fast then goes back to consistent below 1/2 throttle.

You shouldn't be running it at that rpm on muffs- you risk grenading the motor, they need backpressure when running that fast. Look at the priming system for splits in the hoses or cracked t's. At the same time as rebuilding the carb, did you check the condition of the float? Is the float installed the right way around and was it set at the proper height, parallel with the carb body when the carb is inverted?

Also , when you cleaned the carb was the high speed orifice cleaned out too? This sounds totally fuel related, carb specifically to me.

 

[kenmyfam]

Re: cutting out at full throttle

Don't rev it on the muffs !!!! Potential motor explosion as said already. Agree that the money is on a fuel issue right now. Get it in the water to check it out properly though.

 

[ahenderson50]

Re: cutting out at full throttle

Well good to know not to rev it on muffs, no ones ever told me that before. I did check the float and make sure it was parallel. Also blew in the intake valve upside down and right side up to make sure it was seating right. I took both the low speed and high speed out and cleaned them when I rebuilt it. I will check for cracks in the priming system tomorrow. If yall thiink of anything else I need to check or if anyone else has any ideas please let me know. Advice so far has been greatly appreciated!

 

[ahenderson50]

Re: cutting out at full throttle

Ok, I checked the priming system and hoses and couldn't find any cracks or holes. When I bought the motor the guy gave me two new coil packs cause someone told him that may be the issue then not so he never installed them. So I put these on. Now I can't get it to fire. Just checked and they are the right part number. Boy my issues are piling up...

 

[kenmyfam]

Re: cutting out at full throttle

Ok, I checked the priming system and hoses and couldn't find any cracks or holes. When I bought the motor the guy gave me two new coil packs cause someone told him that may be the issue then not so he never installed them. So I put these on. Now I can't get it to fire. Just checked and they are the right part number. Boy my issues are piling up...

Try the old ones back on again.
let us all know results.

 

[ahenderson50]

Re: cutting out at full throttle

Well I put the old coils back on and that fixed the firing issue. I still don't have the carb back quite right or something. I must have missed something. When I try to adjust the carb, I've been starting with backing out 1 and 1/2 turns. But it doesnt seem to matter if it's all the way in or backed out 3 turns it still runs the same. I had to adjust the throttle to where the butterflies are open just a little for it to start. I'm thinking it may be time to take it to a professional..

 

[bktheking]

Re: cutting out at full throttle

So put the old ones back on and get it to start again. Can you shoot a video and post on youtube, I would be nice to see what it is doing. Without the motor running inspect everything to do with throttle and carb, check to see if the butterfly opens up fully at WOT and check to see if anything is loose. If you sure the carb isn't the issue move from the carb back, could be line,primer bulb, fuel pump etc etc etc. A motor pulsing can only do so if it's getting gas and then not getting gas. It could be a ignition problem but you need to rule out fuel first. Any time i've had an engine rev up and down it's been fuel related.

 

[bktheking]

Re: cutting out at full throttle

Well I put the old coils back on and that fixed the firing issue. I still don't have the carb back quite right or something. I must have missed something. When I try to adjust the carb, I've been starting with backing out 1 and 1/2 turns. But it doesnt seem to matter if it's all the way in or backed out 3 turns it still runs the same. I had to adjust the throttle to where the butterflies are open just a little for it to start. I'm thinking it may be time to take it to a professional..

WRONG ANSWER! You can fix this yourself, don't waste your money paying someone else to fix something you can fix. The slow speed adjusting knob only has an effect at idle speed. As soon as you go off idle that knob does squat. How did you clean the carb? Did you dissassemble, remove welch plugs, inspect the orifice for dirt, soak it in carb cleaner over night and blow it out with compressed air. Check it again, I still think it's carb related. I've seen people have to soak and clean carbs 3 times before they start working properly.

 

[kenmyfam]

Re: cutting out at full throttle

WRONG ANSWER! You can fix this yourself, don't waste your money paying someone else to fix something you can fix. The slow speed adjusting knob only has an effect at idle speed. As soon as you go off idle that knob does squat. How did you clean the carb? Did you dissassemble, remove welch plugs, inspect the orifice for dirt, soak it in carb cleaner over night and blow it out with compressed air. Check it again, I still think it's carb related. I've seen people have to soak and clean carbs 3 times before they start working properly.

Agree 100% at this point.