dt65 low power when planing

[Coosa]

I have a 1988 dt65 that runs fine out of water; however, when in the water, engine loses power when trying to plane out, and then stalls. when running at WOT, there are no problems.I have had carbs rebuilt.Do they just need adjustment?

 

[bossee]

Re: dt65 low power when planing

Hi,<br />1) What prop do You use? (Suzuki orginal aluminium prop?) Pitch and diameter?<br /><br />2) What is is RPM at WOT?<br />The recommended RPM at WOT on DT65 is about 5500-5600.<br />So close to that should be fine.<br />If You get less RPM at WOT it could mean You have a prop with to much pitch so it has difficult then to keep RPM up when You accelerate.<br />Rule of thumb: 1 inch change in pitch result in 150-200 RPM change.<br />So If you for example select a prop 1 inch less pitch you will get 150-200 more in RPM.<br /><br />3) If You squeeze the fuel bulb while accelerating - does it help then so that the outboard can keep the power all way trough WOT?<br />If that helps it indicate a fuel delivery problem.<br />Check the whole fuel system from tank (including inside tank) via fuel line, bulb, filter, fuelpump (rubber diagraphm set) to carburators. And fuel connections. The fuelpump is high on list of suspected items to check and replace then.<br /><br /><br />Possibly the carburators need some adjustment.<br />On a DT65 1988 it is possible to adjust:<br />- Float level distance from carburator body to bottom of float, should be 0.39-0.47 inch.<br />- Idle speed (factory adjusted), can be adjusted during operation by turning the pilot (idle) air screw. Lightly seat the air screw and turn out 1 1/4 - 1 3/4.<br />There is also reed valves that control passage of air-ful mixture into the crankcase. Reed stop opening on DT65 1988 should be 0.37-0.38 inch.<br />I do not think any of this is the problem with Your outboard.<br />Trottle adjustments of full closed - full opened can also be performed on no 2 carburator and then adjusting the linkage so carburator no 1 och 3 follow. I do not think You should bother with that adjustment but it is rather easy to check.

 

[Coosa]

Re: dt65 low power when planing

thanks for the reply Bo, <br /><br />1)The original prop is still in use to the best of my knowledge.<br /><br />2)The RPM's, at WOT, check out with your suggested range.<br /><br />3)However, I reviewed your suggestion about the fuel delivery and found that at WOT, the primer bulb loses pressure and air bubbles exist inside the in-line filter.When idling, the same problem is present.I went to Wally-World and purchased a new tank, fuel line, primer bulb and filter.I Will keep you posted on the results.<br /><br />Thanks for the specs. on DT65 carbs. That's good information to have handy.

 

[bossee]

Re: dt65 low power when planing

Hi,<br />The fuelbulb should stay hard after squeezing it. Make sure You mount it in right direction. It is an arrow usually on it and it must point in direction of fuelflow (towards the engine).<br />When You write "in-line filter" is that an extra fuel filter mounted in the fuel line? There is a fuel filter on the outboard itself as You probably have seen. Make sure that filter is cleaned also.