1988 dt150 wont go

[cds111]

1988 dt150 wont go after putting in gear, usually dies. runs/revs fine out of gear. idles a little low and rough. has good compression on all cyl's, new plugs, new fuel filter. its on a 24 foot pontoon. any help would be appreciated. thx

[Solarman]

Usually a brief history of what happened since the last time it was running good can be very helpful to tell us what could have changed. You have to be our eyes, ears, and hands on this side of the monitor.

Sounds like carbs need to be cleaned, maybe check fuel pumps.

Post back when able to help us help you. Good luck.

[cds111]

I just got the motor last year so I don't have a lot of info about it except that the boat it came off of was last tagged in 2013 so motor has set for a few years. runs pretty good in neutral but doesn't idle the greatest. looks like I will be pulling the carbs.

[Solarman]

Do you have a manual?
The most important areas of the carbs to clean are the pas-sages for fuel and air, then the small holes in the jets. Use compressed air to blow through all those areas (not wires), after they soak. Do not mix up the jets between carbs, and all air-mixture screws should be set by the manual identically, and not changed. The float level settings are also important, if float is set too high, fuel runs out throat of carb. If set too low, float bowl will run out of fuel at higher rpms. Always remove needle valve seat, and inspect any debris behind it (this could identify if fuel pumps are coming apart. Then reset float levels each time needle valve seat is installed.

Also, be careful with throttle position sensor (TPS) some have to be set up with special connector if changed.

Before pulling carbs, make sure the gear counting coil is mounted properly, and reading each tooth of flywheel, this coil along with tps, and other sensors tell the control module what the timing should be for the rpms the motor is running at.

Good luck, post back when able.

[cds111]

well I went to the marina yesterday to run a few tests and pull the carbs and something else went wrong. I checked for spark on all 12 wires and all was good. ran a compression check and all cylinders had 120 psi. while checking for spark it was idling a little high then it started shifting/banging into gear on its own without touching the controls. did this a few times then it stopped but I couldn't make it go into gear with the controls. it also stopped pumping water so my beast guess is something happened to the lower unit. I'm going to get it back home this weekend and pull the lower unit.

[cds111]

driveshaft broke so I sold it.