DT85 stalling & Difficult to start

[tryhard]

g'day all

1st post so be Gentle !

I have a Suzuki DT85 - 82' model.

went fishing a couple of weeks ago and after a few hours of mostly low speed (just above idle), the motor stalled & would not re-start.

I pulled the plugs off & they were wet so cranked the motor & dried the plugs but it still would not start.

I have now done the following:-


1. warmed motor up & did compression check with all spark plugs removed
top Cyl. 140 psi
Middle 150 psi
Bottom 150 psi
(3 readings per cylinder)

2. Went and bought new plugs - re-gapped plugs.

3. Checked to see if there were drain plugs on the carby fuel bowls - None

4. Tilted motor all the way up & pumped the primer bulb to see if it was possible to tell if same amount of fuel came from each jet. not able to tell - looked the same to me !
What I did see however was that when I sqeezed hard, there was fuel squirted from the carby 'over flows'?

5. whilst in the full up position, I squirted carby cleaner at the jets & then let it drain.

6. I disconected the fuel inlet hose for each carby & squirted carby cleaner into each one (unsuccessfully I think) - I'm going to have the carbies rebuilt so if I ended up moving gunk & causing more blockages I figured all I would achieve is complete justification for full service by the professionals - right ?

7. turned the motor over ( no plugs in ) - then put plugs in reconnect fuel from main tank & final check before starting..........this is where it gets a little interesting

8. connect water & started motor - motor runs 3 minutes - hunts for fuel & dies - re-start motor, motor hunts after about 3 minutes - squeeze priming bulb to find it's gone soft - motor continues to run then dies again.

9 New tact required ! - connect aux. tank place on ground next to boat - start motor, motor runs about 5 minutes this time.

10. Re-locate aux. tank to rest on topside of boat slightly higher than motor - motor runs & runs & runs - stopped timing after 25 minutes

11. whilst the motor is running I remove the bottom plug lead & note motor changes tune - disconect middle - no noticeable change in tone - interesting & not what I was expecting , connect & remove top lead - no noticeable change in tone ......
anyone want to comment on this? I thought I'd get a noticeable miss for each cylinder????

12. pulled plugs for a look, the bottom plug had quite a fair bit of carbon whilst the middle & top were a little darker than I'd anticipated.

I believe that I have possibly got an issue with the fuel pump, I thought that the motor should drag the fuel up from the aux. tank on the ground (2 feet) & plus the fact that when raised to slightly above the level of the motor there was no problems.
All this plus the fact that it was not dragging the fuel from the main tank. Am I jumping to conclusions ??

I have been told that the fuel pump for this motor is dis-continued, does anyone know if you can still get the parts to rebuild the pump, if not is it possible to retro fit a different pump ?

thanks

 

[JUSTINTIME]

Re: DT85 stalling & Difficult to start

try brownspoint for parts
i would rebuild the carbs
replace fuel pump
replace filters

 

[Crapduster]

Re: DT85 stalling & Difficult to start

Hi Tryhard,

I have an 86 Zuki dt85 that came on the boat I bought in Nov. 07. From the beginning it would start and sometimes idle, but only with a fuel enrichment system someone before me had rigged up It would most of the time bog down and stall before you could get it going... battery would run down from cranking and cranking it; when you finally did get it going it would run great at 3500rpm or above. Some history on my motor: the oil pump has been disconnected and the oil tank has been removed and all the holes plugged; I run 50:1 pre-mix. If there were any alarms or sensors those have been disabled. The suzuki choke was disabled (wire unplugged) and a choke from some other brand was mounted to the side of the carbs. The choke has a fuel line coming in and feeds three fuel tubes, one into each carburetor where the oil lines used to feed into the motor when it was stock... all this was done prior to me. When you press the key in to choke, instead of closing butterflies, it actually dumps some fuel into the carbs... this was some mechanics idea of how to fix a hard start problem and was the only way to get the boat started; I hooked up the normal choke and the boat would not start until I hooked this "fuel enrichment" system back up. I also had leaks at various points in fuel lines on the motor. All of the problems I have encountered fall into one of these categories: lack of maintenance, improper installation of parts or not addressing the root cause of problems.

Just today I put the boat on the water and it ran pretty dang good (an 8.5 out of 10). It needs some adjustments to idle and timing to make it a 10; I have a Zuki manual on the way so I can do the link and sync stuff everyone talks about. All the hesitation problems are gone, the motor runs and sounds much stronger, and it starts on the first turn cold, usually without choking it (the normal butterfly choke is hooked back up now). I have disabled, but haven't taken the old rigged up choke system off yet, maybe after another outing or two I can get that thing off my motor. It is reliable enough now that I have no fears of bay fishing with it, up until now I would only take it on a smaller local lake so I could always get back to dock with my trolling motor if I had to.

Let me tell you the work I have done and the parts I have replaced to get it running good.

Replaced every piece of fuel hose in the engine due to leaks ...tedious but well worth it. Use the right clips and the right size/type of hose. This is much easier to do if you are planning on pulling and rebuilding the carbs.

Rebuilt fuel pump with a diaphragm kit. Needed it.

Replaced the fuel bulb and line from the water/fuel separator to the engine.

Checked the water/fuel separator ...it was fine. Cleaned the fuel screen in the clear bowl at the back of the motor.

Replaced plugs and gapped them correctly... last plugs were never gapped ..again, not me.

By far, biggest difference made was the carb rebuilds... when I pulled the carbs, two out of the three carb to engine gaskets were on backwards... they are fitted and if they are on backwards they block a good portion of the intake airflow... whoever rebuilt the carbs last was not watching what they doing and this almost certainly had some to do with the poor running condition... The carbs looked really clean, but I went ahead and stripped them down, soaked them in a gallon of berrymans, scraped old gasket and got them squeaky clean and then installed the carb kits and new gaskets. Really thought this was going to be harder than it was.

The air idle screws were several turns too far out and after the carb rebuilds these were set to factory specs. I adjusted these while I was on the water today and it it surprising how just a little bit of a turn can make a difference in the way the motor runs.

The lower unit has had some water in it, but just a little bit, gear lube still looks ok. I will be addressing the lower unit in the next month or so... At that time I will have the impeller replaced, all the gearcase seals and the lower unit prop seals replaced. Will also be replacing all the gaskets that go in the drain/fill/flush plugs on the lower unit and have the lower unit flushed.

I made a list of every last nut, bolt, screw, gasket or o-ring that needs to be replaced or is missing and ordered those along with the shop manual. For me it paid to have the parts list that I downloaded from brownspoint marine.

Hope this helps some... the directions aren't specific. I can help with pointing you to online parts and specifics of what I have done so far that has worked for me.

CrappieDuster

 

[sc_shane]

Re: DT85 stalling & Difficult to start

Welcome to iboats! This place is awesome! Wow - looks like crapduster went all out!

Definitly rebuild your carbs, and, while you're doing that, go ahead and replace the fuel filter. Just doing these two alone is going to help a lot. If that doesn't do the trick, I'd look to see if you can find a replacement for the fuel pump. That's going to be your most expensive part, but you might get lucky with the other two and not have to do it at all.

Keep posting questions in here. A lot of advice will come (like mine!). There are some really good mechanics on here that are great for giving advice and more. Good luck!

 

[grid]

Re: DT85 stalling & Difficult to start

The fuel pump seems to be where you're headed here. Back off the (2) 10MM nuts holding it onto the block. Move the pump slightly away from the block and squeeze the primer bulb. I'll bet fuel shoots out the back of the fuel pump. You can get a rebuild kit for it from brownspoint, or your local dealer.

 

[tryhard]

Re: DT85 stalling & Difficult to start

Thanks all for the replies.

Grid,
I will check to see what happens when I loosen the bolts & squeeze the primer, but that wont be untill the weekend.

Question for you, what does it mean if the fuel comes out of the back of the pump? stuffed diaphrams?

It looks to me that the pump is pretty much a solid piece of alluminium plate at the back, but I stand to be corrected.

Will let you know how I go.

 

[Crapduster]

Re: DT85 stalling & Difficult to start

In case you need some parts for that fuel pump after you test it...

This is a link to a .pdf that has a breakdown of every part on your motor.
http://store.brownspoint.com/pdf/DT85(80-82).pdf

If you look up the original part number for a diaphragm kit for your pump it comes up with this:
Part No: 15170-95500
Description: Replaced by 15100-7281V

Part number 15100-7281V is the same kit that I installed. The price is $17.56 for the kit and it is easy to install. In my opinion, if you are not sure how long ago the pump was rebuilt, for $17.56, some shipping and an hour of DIY labor it's cheap peace of mind. I am guessing any marine mechanic shop would be minimum $200 for the fuel pump rebuild. This is the link, as you can see this kit replaces part numbers for at least 80'-86' http://store.brownspoint.com/search....1&txtsearchParamCat=ALL&subcat=&txtCatName=1

Here is a link to carb rebuild kits; same ones that went on my 86' dt85.
http://store.brownspoint.com/suzuki_page_01.asp $22.41x3 and 4-5 hours of DIY time if you're slow like me

Hope these links help if you need replacement parts. Post back and let us know what happens after the weekend when you test.

 

[tryhard]

Re: DT85 stalling & Difficult to start - success !

Re: DT85 stalling & Difficult to start - success !

G'day all,

following up from earlier, I have now rebuilt the fuel pump.

Ran the motor from the aux. tank on the ground - No problems

ran the motor from the main fuel tank - no problems - Whoo Hoo !

Next thing is to get it on the water & see how it goes - might try tomorrow if I get time.

Only one stuff up - thought I might drain the water separator / filter and watch it fill whilst running the motor. Problem is I over tightened the bolt & cracked the glass bowl - bugger !!!! I was going to replace it but not yet -oh well.

Thanks for the help folks

 

[Crapduster]

Re: DT85 stalling & Difficult to start

Good to hear about the improvement. Hope all goes well on the water for you

One question, the fuel bowl you are talking about that is cracked, is that the one mounted by the fuel pump or you have a separate water/fuel separator that was damaged? I couldn't quite tell from the post if you indeed have a fuel/water separator or if you were speaking of the bowl by the fuel pump which is just a screen and not a separator. Is it possible to take it off, clean it really good and then super-glue the crack to seal it. I can't help but think that even with a small crack you are going to suck some air into the lines.

CrappieDuster

 

[tryhard]

Re: DT85 stalling & Difficult to start

Crapduster,

(where do you come up with a name like that anyway ?)

The filter separator is separate from the filter in the motor - it is externally mounted, same as a diesel type filter separator.

I'll tell you my tale of woe now !!!

Took it out on the water this morning.

All seemed to go well and then, I had the same problem re-occur.

This time when I pulled the plugs they were dry.

The motor refused to start at all.

I pulled the air box off & sprayed a bit of 'Start Ya bastard' but the motor only ran on that & did not run on the petrol - that is it refused to keep going.

I put the 2 new spare plugs I had in & that seem to do the trick (even though the plugs that were in there were also new.

once going, the motor ran fine again - called it a day at that point.

When I got home the motor started on the flusher but there was a definite miss then she stalled as though it was out of fuel & I could not restart it.

I have given up for now, next stop is the mechanics.

 

[Crapduster]

Re: DT85 stalling & Difficult to start

Sorry to hear about the on-going problems. Hope it gets sorted out real soon.

I meant for CrapDuster to be a play on cropduster (the plane) as a play off crappie (the fish) ...I figured since I only really use it on fishing/boating forums and on crappie.com that it would be a good nickname, most folks look at it and think poopduster That's why I sign all my posts at CrappieDuster.