Logo
FULL SITE MENU

Johnson 150hp fast strike motor stalls while accelerating quickly

B

Bowenlhzn

Member
I have a 1993 Johnson fast strike motor, it ran fine at the beginning of the year last year, but later on I started to notice that if I accelerated quickly it would bog down and die. It would idle fine and if I accelerated quickly it ran just fine. Finally toward the end of the year it got to the point that if it was In gear and I wasn’t giving it gas it would stall the too. I’m not sure what the problem is. I was hoping that I may be able to get some information as to what you guys think and hopefully it’s something I can fix myself without needing to be charged an arm and a leg for a shop to fix it.
 
I looked at all of the float bowls and a couple are warped but all 6 have a crack in the same place(some worse than others) I find it strange that all 6 have cracks in the same place. I tried to include a picture of the crack but for some reason I am unable to. Is there a common pace for float bowls to crack? mince cracked on the side just to the right of what looks to be a brass bead.
 

Attachments

  • IMG_2080 (Small).JPG
    IMG_2080 (Small).JPG
    80.6 KB · Views: 78
Last edited:
Do not know who worked on it.----But most folks are unaware of the torque limit on the screws for the bowls.------I believe it is in the order of 10 INCH LBS and that is not very much.-----So from where I sit I say they were tightened way too much.
 
racerone said:
Do not know who worked on it.----But most folks are unaware of the torque limit on the screws for the bowls.------I believe it is in the order of 10 INCH LBS and that is not very much.-----So from where I sit I say they were tightened way too much.
Click to expand...

ok, good to know for when I’m putting them back on. I ordered 6 new bowls and thought I might as well rebuild the carb while I had them off so I got 6 rebuild kits. They should be here Wednesday next week. Hopefully this fixes the problem.
 
Do not know who worked on it.----But most folks are unaware of the torque limit on the screws for the bowls.--​
Click to expand...
This is correct and limit s 18-24 inch lbs...there is also a torque pattern like a cylinder head a X pattern.
 
so I replaced the float bowls and rebuilt the carbs, I took it out to the lake and wasn’t able to go over 2500 rpm while in gear. Also the motor started to stall while in gear. I did a compression test and the three on the one side and the top on on the other side were all about 120psi then the middle one and bottom one on the same side were 90psi and 100psi. I’m guessing this is my problem. Any ideas on where to go from here?
 
Compression test was suggested over a week ago.----Now I suggest you remove cylinder head where the low compression is.----Likely will tell a story.
 
I finally got a chance to work on the boat again this morning, it’s been a little chaotic recently. I removed the cylinder head and the head looked fine, but the piston had a buildup of black stuff on it. The cylinder walls looked ok as well5C4C294A-4CC6-45EA-9115-6B16FC1F4A2A.jpeg
 
So I put the cylinder head back on and ran a bunch of Seafoam through it, it seems to be running much better now, no more stalling. Still need to take it out to see if I can get over 2500 rpm in the water. Tested the compression and still have low compression in that #3 cylinder. Do you guys have any idea as to what could be causing it. I ordered a new O ring for the cylinder head to see if maybe that’s the problem. Other than that I’m not sure where to go from here about the low compression. Piston didn’t have any play and there was no scoring, I rebuilt the carbs so that’s not the issue. What else could be causing the low compression?
 
Cylinder #3 has marking on the cylinder wall.----Some will argue.----I would take this motor apart for a look at that #3 piston and rings.
 
Back
Top