89 DT150 Intermittent Power Loss

[zachboyer]

Background - I had my boat in a shop in Tulsa a few weeks ago for some new motor mounts and asked them to check out my motor and tune it up if need be.

Long Story Short - I got my boat back and the trim gauge did not work and the alarms on the boat didn't work. A few days on the lake later the boat would bog at about 3k rpm and I wouldn't be able to get up on plane. (pretty bitter about this shop)

Yesterday - I was on Keystone lake and ran about 10 miles great no problems. The second half of the day I started the boat after sitting for about an hour and it had no problem planing off. Ran about 1 mile slowed and idled around. Went to get back on plane and couldnt. The motor would be very sluggish and no matter how easily I leaned into the throttle it wouldn't rev higher than about 3k. So I had my buddy get on the bow of the boat to help me plane out. Once I planed out I could hear the motor free up and it would run ok... After some more getting around it was time to head to the ramp, so another "get on the bow moment". It was about a 10 or 15 mile run to the ramp and the boat was running ok ok plane but I knew something was still wrong. I couldn't get the boat over about 46mph gps. It will normally run 60mph gps at about 5800pms...

The first time this problem ever occured I was running at about 3k rpm (by my own choice) for about 1 mile and when I actually went to plane off it wouldn't, But didn;t have a problem the rest of the day.

I have played with the rich/lean fuel mixture to no avail. what should I look at next?

[Solarman]

dt150, '89 running issues

The mixture adjustment you're playing with only relates to low speed idling.
Have you gotten the electrical problems straightened out yet? I don't think the trim issue would affect the motor running, but the alarm issue may.
If there is a loose connection, or something shorting, it could be related?
It may also be a good idea to check your fuel filters, to see if actually clean?
Once electrical issues are ironed out, then let us know if still having problems.

[zachboyer]

I don't have a trim issue, the power loss just won't get the boat on plane unless I make it plane out, then the motor frees up. When it doesn't have an issue it jumps on plane in a heartbeat.

Is there a wiring diagram anywhere for the motor. I do not have any lights come on, just the alarm doesn't work anymore

[Solarman]

Background - I had my boat in a shop in Tulsa a few weeks ago for some new motor mounts and asked them to check out my motor and tune it up if need be.

Long Story Short - I got my boat back and the trim gauge did not work and the alarms on the boat didn't work. A few days on the lake later the boat would bog at about 3k rpm and I wouldn't be able to get up on plane.(pretty bitter about this shop)

I was referring to the trim gauge affecting motor. Have you gotten the alarm and other electrical issues straight?
These things may be related?

[zachboyer]

Oh ok, no I have not solved them. Is there a wiring diagram for the motor anywhere?

[Solarman]

89, dt150

They do have manuals you can download online. But you will have to google it, I don't know where to go for that. You could start a new thread asking where to find one. Am sure there are many here that know.

[zachboyer]

Still having this issue, went through all of the wiring in the boat and everything looks solid... I replaced all of the fuel lines in the motor and to the tank, basically pulled everything off of the motor and looked around a bit for anything hinky and couldn't find anything..

[BillCon]

just out of curiosity, take the pilot jets out of the sides of the carbs, those are the ones that do not adjust, near the upper part of the carb,little brass flat head slot screws, they help in the fuel/speed transition from the idle jets to the main jets and nozzles, if one or two of them gets dirt in them you cant plane out.

[aquamort]

Did you take it back to the workshop? Obviously it didnt behave like this before taking it there? You would have to look at the trim gauge etc being connected to the issue too? Unlikely coincidence i would think?

[Solarman]

dt150, 89, carbs, running & electrical issues

Ok, was motor running good before taking to that shop for the mounts, what mounts did they replace, and did they say they gave it a tune up? Replace anything? Adjust anything?
I'm trying to get an idea, of what they might have done that could have created your problems?

Post back when able.

[zachboyer]

The shop is Ugly Johns out of Tulsa, The guy turned out to be a shotty guy. I should have stopped their check, but you snooze you lose.

They tried telling me they didn't think the trim gauge was working when I brought it in and the alarm too. Assholes.

-Service Lower Unit
-Replace Water Impeller
-Replace upper motor mounts / Had to remove power head to replace upper mount bolts
-Repair shift linkage on lower unit (This bent when the motor mounts gave way and I about lost the motor)


I have gone out fishing everyday the past 2 weeks and the boat only did it to me twice, but I was able to get on plane and then it freed up. I was only able to get up on plane because of weight.

I had my buddy with me one of those days and the boat ran great then gave me this problem. I was able to get up on plane after about 20 seconds then the rpms gave way and i was going 50mph.

Added note: I just warmed up the motor in the driveway and did a compression test and got 81PSI on every cylinder.

The motor has ran great for the majority of this season so far.

[zachboyer]

If this happens the motor bogs around 3000-3500 rpms, If I get on plane It acts fine although it feels like its surging sometimes when on plane (Only when it bogs down)

Very intermittent. I can not reproduce the problem on command

[Solarman]

If this happens the motor bogs around 3000-3500 rpms, If I get on plane It acts fine although it feels like its surging sometimes when on plane (Only when it bogs down)

Very intermittent. I can not reproduce the problem on command

Ok, if you played with the idle mixture screws, return them all back to original position. They should all be identical. So many turns open from lightly seated closed.

Have you pulled the plugs, this can identify how each cylinder is running (don't mix them up), if plugs are old, replace.

Often surging at higher speeds relates to fuel flow, if pumping bulb while having this happen changes anything, it is probably fuel related.

It is also possible you might have gotten some bad fuel? If possible, when checking fuel separator pour the contents into clean glass container, to see if debris, or water was bought with fuel. It does happen, often, with some stations more than others.

Do you have a manual for your motor? It will tell you what to set mixture screws at.

Post back when able.

[zachboyer]

I reset all the screws according to manual, plugs look great but I have replaced anyway. And I have been through about 10-15 tanks of fuel since this originally started.

I took a video of it today I just don't know how to get you to hear it(or see it)

[Moonlighter]

I reset all the screws according to manual, plugs look great but I have replaced anyway. And I have been brought about 10-15 tanks of fuel since this originally started.

I took a video of it today I just don't know how to get you to hear it(or see it)

Upload it to YouTube or photo bucket, then copy and paste a link from there to a post you put here.