Suzuki DF90A Stalling

E

easternshore22

New member
I am having problems with my outboard that is driving me crazy.

Symptoms: Engine stalls idling, going at cruising speed or at WOT, Can be 2 minutes from starting or 15 minutes. Engine stops, beeps twice (indicating stalling) and no error codes in diagnostic screen. I squeeze the primer bulb a couple of times and starts again. Then it happens again and repeat the cycle.

The fuel system has (in sequential order):
- Two fuel tanks
- Selection valve
- 10 micron filter
- Primer bulb
- Low pressure filter
- Low pressure pump
- Fuel vapor separator that includes high pressure pump and pressure regulator
- High pressure filter
- Injectors
- I use regular gas with stabil + startron

I replaced everything between the tanks and low pressure pump with the exception of the selection valve. The problem still exists and seems that it is more frequent.

What I have observed:
- When it stalls, the bulb is not flat, just soft
- When I prime again, I hear air coming out the vapor separator until the bulb gets hard
- If I notice that the engine will stall, I reduce RPM and recovers
- I checked for air leaks when priming, and can not find any since I can get the bulb hard and stays like that
- No kinks even when the engine tilting up or down, left or right.
- I hear the high pressure pump working when I turn the switch to on (based on the shop manual, it turns on at 100% for 3 seconds to pressurize the system).

My next step is to replace the high pressure filter, but not sure this is the problem. The problem happens at high and low RPM, it seems that randomly somewhere the fuel line gets obstructed. Maybe the pickup at the tank get's obstructed?

Any ideas?

Thanks,

Franco
 
We had the same problem with both our 40 hp Suzukis. Nobody could fix them, not reasonably anyway, and we ended up replacing them with Yamahas.
 
I just had a real headscratcher in my fuel supply, it turned out to be some defective fuel lines sold by Sierra a few years ago. It is defective, and the inner liner will delaminate and separate and collapse separately from the outside hose. This will not show up in a pressure test, with soapy water, it took quite a while to figure it out. They sold many miles of this hose. It is white or grey with a gloss finish. See:

http://www.yamahaoutboardparts.com/foru ... 22055.html

http://www.c-brats.com/viewtopic.php?t=20487

Roger
 
Here's a great troubleshooting sequence:

Joined: 02 Nov 2003
Posts: 11415
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2006
C-Dory Model: 22 Cruiser
Vessel Name: Thisaway
Photos: Thataway

PostPosted: Sun Sep 08, 2013 12:11 pm Post subject: Reply with quote


Starting at the bottom of the tank here is what could be an issue: intake screen over the fuel pickup clogged. The pickup tube could have an air leak (I have had a pin hole in one, which pulled air, rather than fuel). The anti siphon valve at the top of the tank--may or may not have an Elbow attached. Anywhere along the line there could be a pinch, or even in an old line, broken down inner wall of an old hose which has collapsed and would prevent fuel from flowing. At the filter--could be air coming in any of the fittings, hose clamp leaking at any of these places from anti siphon valve to the squeeze bulb. The filter gasket or water drain (if it has one) is not seated properly. I have also seen Teflon tape which covered an intake or discharge fitting out of a filter, when it was not properly applied to the threads. The bulb could be bad--and I always carry a spare bulb. If there is an obstruction, the bulb usually remains collapsed. One other place, but unlikely in this scenario is a clogged fuel vent.

I agree that it seems like it is sucking air. I usually keep an outboard tank around, so I can put that in the boat, and do diagnostics--see if the leak is before the tank buy hooking the house out of the anti siphon valve to the outboard tank. If it works fine, then the air leak (or obstruction) is in the anti siphon valve or in the tank pickup. Work your way up the system and you will find you leak. Another way to find a leak is to paint all of the fittings with a soapy water solution, put slight pressure on the fuel line from the tank--and see if bubbles form at the fittings junction or around the hose clamps.
_________________
Bob Austin
Thataway
 
Thanks everyone for the answers.

All the lines, 10 micron filter and bulb are new from west marine. Since it is an old boat I started with that.

One more detail, the engine has 150 hours.

Does the position of the bulb really matters (I mean pointing up or down)? I never heard about that, but I will check anyways.

It seems that my next step would be to check the tanks. I see if I can borrow an external one to test before removing them.

Thanks,

Franco
 
We had a similar problem with a f-115 Yamaha . We changed out 10 micron filter and fuel bulb that did not help . then we took out fuel pickups without the ball bearings anti siphon valves that did the trick no more fuel problems We use only non -ethanol fuel with startron and change out filters every 50-75 hrs. With all new hoses and filters it might be the fuel pickups . Good Luck Jim
 
Yes I agree... You have a fuel supply issue and need to check the entire system., and there are differences in primer bulbs and installation skywards or vertical is important ....some feel OMC/Bombardier bulbs are the best .. something to check
 
Roscoe, if you still have the non functioning Suzuki 40 hp motors, I'll take them off your hands. Two motors don't go bad in the very same way. Your mechanics must have been really really really bad to not have been able to get to the root of two Suzy motors going bad in the very same way and fix them at a reasonable price compared to brand new Yamahas.

At least I'd like to hear the story of what the problem was with them and what trouble shooting took place. My Suzuki's are excellent and if I run into a similar problem with mine some time, I'd like all the info I can get on other Suzy problems.
 
The only time I have ever had the problems you describe was when the antisiphon valve located inside the elbow fitting coming right off the tank began to malfunction. With the engines running, lean down and listen as close as you can to this valve. In my case I heard what sounded like electrical arcing (caused by the ball inside the valve not able to move properly).

If your fuel tank is below the fuel port on your engine you don't need one. Super easy fix if yes. Place antisiphon valve in a vice, take a screw driver that will fit inside, and then take a hammer and knock it out. One pop with the hammer and it will be out.

Good luck with the research.
 
All good suggestions--I agree with Matt--that if all else fails, it could be the anti siphon valve.

Yes, the fuel flow out side of the bulb should be up. It has to do with the valves in the bulb. But you may notice that during priming.

I agree the separate fuel tank is a great idea--borrow one, if necessary.
 
Thanks everyone for the help. This is a great site!

I looked at the bulb and it was pointing down. I changed the layout to point up.

I also checked the pickup line of one tank and it came out. It was all brittled. I guess they were built before ethanol and after 18 years they reached the end of their life.

The next step will be to get a pair of new ones and also borrow a separate tank to check.

I will post with the results after the weekend.

Thanks again,

Franco
 
I posted this a few weeks ago but no one commented so it dropped off the forum. I wonder if it's not the same thing. I'm using a lot of the suggestions above, but still have not found a clear thing as the "problem."

Last fall (2013) before winter I attached a fuel pump to the outlet of the "kicker" motor and drained both tanks. I did not change the fuel filter, thinking that I'd put a few hours on the motor in the spring and then change, so than any "junk" kicked up by the draining or spring refueling would be caught in the old filter. I put about 15 gallons in each tank in the spring, ran the motor about 1 hr on the local lake, but our planned trips to the Salish Sea got scrapped and the boat did not receive any other use until early August.
In early August I took the boat to a Convention in Richland, WA. The marina in front of the convention hotel was $5.50/ night, a lot less than the $119/ night for the hotel. Great convention. I put the boat in the water and just in idle forward & reverse to a dock for 5 nights. Day temperatures reached 3 digits. With the convention over I started the motor and "idled" to the boat ramp. Motor died as I reached ramp. Started, but would not "rev" up. Acted "fuel starved." Maybe time to change fuel filter, but could not budge filter cartridge by hand and had left filter wrench at home. Finally winched boat on trailer and headed to Salish Sea. I had made appointment to a Marina for electronic check up, arrived on time and had them look at motor also. They changed filter and when removed it was only half full of fuel. They put motor on a "muff" and it idled fine for half an hour. OK, problem solved!

Headed to Bellingham, launched boat about 6 pm, idled to visitor dock, spent night, shopped for groceries in morning. About 11 headed for islands. Cleared visitor dock, headed for harbor entrance and applied power and motor died. Restarted, it would idle and then die. Kicker did same. Drifted into some parked boats and they helped tie us up. With some experimentation I could keep kicker motor going by pumping bulb, but could not keep main motor going that way. Used kicker to get to boat ramp, winched on trailer. It was then 1:30 pm on a Friday afternoon. Where do you find a mechanic on a Friday afternoon or would we have to wait to Monday. So we came home.
At home, I attached fuel pump I use to empty tanks to Kicker motor line and pumped into a spare gas can. Fuel came slowly at first, then fast.
I check breather inlets. We have wasp problems here and they often plug up small holes. They looked good and clean to me. I looked at everything I could think of, could find nothing, so took boat up to reservoir and ran it. big motor started rough but quickly smoothed out. I ran around the lake in circle at 20 knots for an hour (afraid to get too far from the dock). Motor ran fine, no hesitation after first start.

So, it is cured? Dare I trust it? What else could it be?
 
Two Bears":262v6ds7 said:
Fuel came slowly at first, then fast.
Click to expand...

Probably you solved the issue there. If you sucked the obstruction out of the tank, it is probably a permanent solution, if the obstruction fall back to the tank, you will need to clean the tank.

That is what I will do with mine once I take the boat out of the water since part of the pickup is in the tank, and who knows what else.

Franco
 
Update:
I connected an external tank directly to the low pressure filter using the bulb of that tank (no components in common with the boat's fuel supply setup). I did not run it like this for long since I did not want to run without the 10 micron filter. It run fine.

The filter maintained the level of gas at different RPMs. I also kinked the hose to block the supply and saw the level go down and once unkinked the level went up. So I can say that the low pressure pump is working.

I repeated the test connecting the hose that connects to one of the tanks to the external tank. It also worked fine (if I kinked the hose, level goes down and after unkinking level rose).

I also depressurized the line after the high pressure pump and when setting the key to 'ON' I could feel (pinching the hose with the fingers) the high pressure buildup in the hose, so that system seems to be also ok.

So I can say that the hose, 10 micron filter, valve, etc are ok. Before the filter would just start getting empty.

One note is that after unkinking, the level rose very fast with the tank connected directly to the low pressure filter compared to connected to the hose that goes to the tank. I assume this is expected due to extra elements between filter and tank?

I am waiting for the replacement fuel pickups to replace and test with the tanks.

Couple of questions:
1 - The old pickups have a stainless mesh at the bottom of them. Is this ok? Why there would be a filtering element in a place not easy to inspect or replace. Both had many of the holes blocked with some black material (residue from the float of the sending unit?)

2 - Should I expect the bulbs to go flat after I block the supply of gas? That did not happen. Does this mean I still have some sort of air leak? I will use soapy water after I connect everything back to check for leaks.

Thanks,

Franco
 
I removed the fuel pickup tube screen and ball and spring in the ASV, checked the elbow fitting but no screens with present) and gas flows directly to the external fuel filter (RACOR, Yamaha, ....)
 
Had to replace my 2005 Suzy 90. My mechanic could not do a permanent fix. Got 1450 hrs on the old engine. Apparently a bad design. My mechanic says new DF90A is a much better engine. We shall see.
 
Back
Top