frank arnold
New member
1993 150 faststrike johnson, just rebuilt and is just finished breakend double oil hrs, so I had not felt this since rebuild but was having same concern before loosing piston causing the rebuild. So Im really concerned.
Engine runs fine until reaching around 4800 rpm as engine starts triming up runs fine then just before the rpms reach 5200 and the "last of the trim travel" it cuts back rpms drop about 500 and will not pick up till I trim it down and let out of throttle.I can trim 3/4 and hold throttle at 4800 rpms and runs 52 mph all day but as soon as trim is enguage to get that last bit of rpms and speed (use to run 5600 rpm @ 61mph gps)the rpms will drop again.
Here are afew things I have done in an effort to cure this :
1.Inspect fuel lines --(anti sophin valve was taken out of tank years ago)-and replaced water seperator filter and the engine screen filter- all seem normal
2.checked prop for blow o out or hub slip-- nothing visual
3.ran different prop -- did same thing
4. moved engine down on jack plate to 4 in below pad--did same
5. recheck syn of carbs and timing -- ok
6.removed high speed jets flushed carbs while they were out changed to next size (req jets for 175 hp)
7. made hard run at lake. removed all plugs check burn all looked dark brownish
8. installed another set of fresh plugs
now Im scratching my head.... want to try something else but running out of ideas fast. Do you think the fuel pump side of the vro is getting week. I took it to dealer and had the set the timing from scratch and route the vaccum/hoses, Did they get them connected to the right places?
I'm thinking of installing a regulated elect gas pump on and double the oil again for testing to see if running out of fuel psi on topend next. ? possible electrail like power pack/coils?
If ya got any Idea let me know. email at [email protected] or respond here I only check this ever couple days.
Thanks!
Engine runs fine until reaching around 4800 rpm as engine starts triming up runs fine then just before the rpms reach 5200 and the "last of the trim travel" it cuts back rpms drop about 500 and will not pick up till I trim it down and let out of throttle.I can trim 3/4 and hold throttle at 4800 rpms and runs 52 mph all day but as soon as trim is enguage to get that last bit of rpms and speed (use to run 5600 rpm @ 61mph gps)the rpms will drop again.
Here are afew things I have done in an effort to cure this :
1.Inspect fuel lines --(anti sophin valve was taken out of tank years ago)-and replaced water seperator filter and the engine screen filter- all seem normal
2.checked prop for blow o out or hub slip-- nothing visual
3.ran different prop -- did same thing
4. moved engine down on jack plate to 4 in below pad--did same
5. recheck syn of carbs and timing -- ok
6.removed high speed jets flushed carbs while they were out changed to next size (req jets for 175 hp)
7. made hard run at lake. removed all plugs check burn all looked dark brownish
8. installed another set of fresh plugs
now Im scratching my head.... want to try something else but running out of ideas fast. Do you think the fuel pump side of the vro is getting week. I took it to dealer and had the set the timing from scratch and route the vaccum/hoses, Did they get them connected to the right places?
I'm thinking of installing a regulated elect gas pump on and double the oil again for testing to see if running out of fuel psi on topend next. ? possible electrail like power pack/coils?
If ya got any Idea let me know. email at [email protected] or respond here I only check this ever couple days.
Thanks!
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