christopher425
Member
Hey everyone,
I've got an '87 Mariner 45hp 2-stroke 4cyl (2 carb) that has no power past 1/2 throttle. She'll crank super easy, idles great, runs great from 1/2 throttle and below. When you try to go any faster she hits a wall and just stays there. If you back off to 1/2 throttle it picks back up and will hold there. I've look and the timing IS advancing with the carbs. Throttle plates are synced and fully open at WOT. It doesn't sound like it's missing any. I pulled all the plugs and they are all the same color, so that tells me they are all firing. She ran great up until I installed the floats in the carbs too low, so I thought that was starving it for fuel, but I went back and adjusted them to OEM spec (5/16") and took it on the lake again....same issue, but not quite as bad.
The first time it started surging as soon as I put it in REV coming off the trailer and it ran WOT for a couple of minutes, then gradually kept dropping rpm's until we limped back to the ramp via basically idling.
After taking the carbs apart and getting the float heights to spec, we took it out again. She didn't surge at all backing off the trailer, idled great, but had no power or increase in rpm's after 1/2 throttle. It ran somewhat better, but still super slow.
This seems like an easy fix and I know there are tons of reasons why it has no power at WOT (I've scoured the internet looking at other posts, but no one seems to post how their issue was resolved.)
nIt ran great up until I over-adjusted the floats, so I'm thinking I did something in advertently and just can't seem to discover what that is. I haven't messed with the flywheel or timing, so I don't think that's in consideration.
Here's what I have done so far:
1) Rebuilt both carbs and thoroughly cleaned (several time)
2) Replaced ALL fuel lines from the tank to the motor
3) New fuel filter
4) Cleaned spark plugs
5) New high-end stator and trigger installed
6) Cleaned fuel tank
7) New primer bulb from Wal-Mart
8) Rebuilt fuel pump
9) Only using non-ethanol gas
10) New switchbox
Things I'm thinking it could be:
1) Water in gas tank from rain (I leave the cap vent screw open at all times to keep it from swelling due to heat/sun)
2) Carbs need cleaning again? (high-speed jet, etc)
3) Fuel filter caught some debris and is clogged
4) Spark plugs need replacing
5) Linkage between carbs/timing arm are slightly off?
Any help is greatly appreciated fellas. Thanks so much!
I've got an '87 Mariner 45hp 2-stroke 4cyl (2 carb) that has no power past 1/2 throttle. She'll crank super easy, idles great, runs great from 1/2 throttle and below. When you try to go any faster she hits a wall and just stays there. If you back off to 1/2 throttle it picks back up and will hold there. I've look and the timing IS advancing with the carbs. Throttle plates are synced and fully open at WOT. It doesn't sound like it's missing any. I pulled all the plugs and they are all the same color, so that tells me they are all firing. She ran great up until I installed the floats in the carbs too low, so I thought that was starving it for fuel, but I went back and adjusted them to OEM spec (5/16") and took it on the lake again....same issue, but not quite as bad.
The first time it started surging as soon as I put it in REV coming off the trailer and it ran WOT for a couple of minutes, then gradually kept dropping rpm's until we limped back to the ramp via basically idling.
After taking the carbs apart and getting the float heights to spec, we took it out again. She didn't surge at all backing off the trailer, idled great, but had no power or increase in rpm's after 1/2 throttle. It ran somewhat better, but still super slow.
This seems like an easy fix and I know there are tons of reasons why it has no power at WOT (I've scoured the internet looking at other posts, but no one seems to post how their issue was resolved.)
nIt ran great up until I over-adjusted the floats, so I'm thinking I did something in advertently and just can't seem to discover what that is. I haven't messed with the flywheel or timing, so I don't think that's in consideration.
Here's what I have done so far:
1) Rebuilt both carbs and thoroughly cleaned (several time)
2) Replaced ALL fuel lines from the tank to the motor
3) New fuel filter
4) Cleaned spark plugs
5) New high-end stator and trigger installed
6) Cleaned fuel tank
7) New primer bulb from Wal-Mart
8) Rebuilt fuel pump
9) Only using non-ethanol gas
10) New switchbox
Things I'm thinking it could be:
1) Water in gas tank from rain (I leave the cap vent screw open at all times to keep it from swelling due to heat/sun)
2) Carbs need cleaning again? (high-speed jet, etc)
3) Fuel filter caught some debris and is clogged
4) Spark plugs need replacing
5) Linkage between carbs/timing arm are slightly off?
Any help is greatly appreciated fellas. Thanks so much!