DT75 stalls under load

"DT-75 (85-87) stalls

"DT-75 (85-87) stalls only under load (engine sat for 2 yrs). Runs fine on idle, high throttle (neutral), and even in gear while on water flush. When in the water it stalls as soon as it goes into gear. If trimmed to just below the surface, I can get it run for a short period.

Boat came from NV 1100' elevation, trying to operate it at 8600' elevation in Colorado.
Is a carb adjustment needed for this change elevation?

I removed the 16" pitch prop and put the original 15" pitch prop on (no help).

I've seen several posts on somewhat similiar issues related to spark plugs, carb cleaning, fuel pump diaphram, timing, idle adjust, etc.

I'm looking for recommended adjustments, and service I can perform (hopefully easiest first).

Also ,looking for service manual for 85-87 DT-75.

This is a difficult problem to diagnose because I can't tell if it's fixed without launching the boat. Would a water tub give the load to simulate the problem?

Thanks for any advice,
Mike"

rebuild the carb and fuel pump

rebuild the carb and fuel pump first

Thanks for the response.

Thanks for the response.

Can you recommend a cleaning solution that is safe for all of the components?

Mike

i like yamaha's stuff in a

i like yamaha's stuff in a bottle

"OK, I rebuilt the carbs and t

"OK, I rebuilt the carbs and the fuel pump. Also replaced the fuel filter and oil filter. The carbs were very clean and I did not find any particles, varnish or crud.
The motor ran GREAT the first trip out once I adjusted the jets on the water. After that, I can only get to ~2000RPM at WOT. It will run all day like this, just won't go any faster. I've pulled the carbs and cleaned them again, even ran wires thru all the holes but no luck. Ran seafoam thru, no luck, still stuck at 2000RPM.
The jets are open 1 turn from closed. Any more open and the motor stalls under load (just like the original problem). Also noticed some oil in the water and some dripping from the prop.
Low RPMs at WOT sounds like a fuel problem yes? The bulb is not collapsing and pumping it at WOT does not help.

Any more ideas?
Thanks,
MGN"

Does it seem to smoke excessiv

Does it seem to smoke excessively?

When first started cold it smo

When first started cold it smokes pretty good but much less when warmed up.

"Still looking for ideas on lo

"Still looking for ideas on low RPM at WOT?

Scott?

JUST-IN-TIME?

Thanks,
Mike"

you need to lean it out at 850

you need to lean it out at 8500
switching props is the quicker way to do it

"I assume you mean a lower pit

"I assume you mean a lower pitch prop?
I already switched from 16" to 15" pitch.
How low do you recommend I go?

Thanks,
MGN"

probally like a 14 or 13

probally like a 14 or 13

"Thanks, one more question.

"Thanks, one more question.

In several other motor forums, they suggest changing to higher altitude jets in the carbs.
Are there such jets for te DT75?

Thanks,
Mike"

yes 130 or 135
u should have

yes 130 or 135
u should have a 140 in there