Suzuki DF50 - won't keep running....fuel pump?

[tegwilym]

We have a "new" (to us at least) 26M with a Suzuki DF50 engine. When I tested it our first time (changed plugs, fuel filter, impeller) it started fine and seemed to run ok. I was hoping to run it 15 minutes (on the hose of course), warm it up, change oil....etc and have it ready for first try.
Nope. Can't keep it running now. What I've done:

• Swapped hoses (all new from new tanks)
  Replaced water separator
  Added a ball valve to select tanks.
  Replaced fuel filter in engine
  Replaced the female fuel connector on fuel line to engine (the male side on the engine is next when it arrives)
  Replaced and gapped plugs
  Seemed to have a clogged "pee" tube, got that cleared and water flows fine (when the thing ran).

What is happening:

• Prime engine until bulb is firm.
  Flip up high idle lever
  Start engine - sounds like it's trying to run, but won't.
  Sometimes runs a few seconds and dies.

Suspecting:

• I don't see much fuel running through the filter
  When key is in 'on' I hear a very faint click in the engine.
  Very faint sound from the high pressure fuel pump
  Checked voltage at the plug - verified 12v for 3 seconds after turning key on.
  I'm thinking the high pressure pump is faulty, and only runs when motor is moved/tipped enough for some fuel to get into the line to the engine

Question about pump as suspect:

• How loud is the pump when its running and sucking fuel before starting?
  I'm sure I have heard the whirring pump sound from our ATV, Motorcycle, Bayliner...when turning the key.
  I think it should have a noticeable sound, but not hearing it.

Any ideas? Do you think my idea is on the right path? Fuel starvation from a pump not working?

Someday, we'll try to sail/motor this thing, but just throwing money and frustration so far.

Tom

[Starscream]

I don't have a ton of useful things to add, but the symptoms you describe match exactly what happened to me when I changed my primer bulb. Despite knowing that they are unidirectional I still managed to install it with the arrow pointing the wrong way (no idea how I managed that, but there it was, backwards.)

[tegwilym]

I did think of that. I removed the two old ones which were hard. I have he arrow pointing from the tank toward the engine. It does get firm and can feel fuel in it. Also, I did check the old one and felt it suck on the arrow input side and blow a little air on the arrow side, so I'm thinking it's something else.

I don't have a ton of useful things to add, but the symptoms you describe match exactly what happened to me when I changed my primer bulb. Despite knowing that they are unidirectional I still managed to install it with the arrow pointing the wrong way (no idea how I managed that, but there it was, backwards.)

[Jimmyt]

You might check this thread...

viewtopic.php?f=9&t=19363

Sounds like you could be on the right track. First, did you verify that you have spark?

If you have spark, then fuel is likely the problem. Do you have a pressure port on the high side to check the pump? I don't have a Suzuki, so I'm not familiar with them, sorry. I have a fuel pressure test gauge, that wasn't terribly expensive. If you have a test port, I'd get a test gauge before buying a pump.

Looks like your high pressure pump isn't too expensive if you DIY.

If you don't have a test port, is there a fitting you can crack open to see if you can tell if the pump is working. Wear goggles and be careful. A 50-60psi fuel spray is probably a bad idea, but if you can't test any other way...

Also, they typically whirr audibly during the initial charging. So if you can get a buddy to click the key while you have your ear at the pump, maybe you can tell if it's running.

[tegwilym]

Yep. I have a spark since I do hear it almost starting, and sometimes I get enough fuel in it to get it running for a few seconds - only in the high idle position of the lever on the throttle. It did run a few days ago after I hooked up the new fuel lines, plugs, filter and impeller. It didn't seem to run strong since it had trouble when I put it in gear. Now it does nothing but some sound as if it's trying to fire up. I think it's just not getting fuel.

The link you sent was a good discussion. Right now I'm wondering how loud the high pitch whirring sound should be for the 3 seconds for priming when you turn the key on? I hear nothing, so that's why I question the pump. I did find a good 12V at the connector so the fuse is good and voltage is there.

Tom

[OverEasy]

Hi Tegwilym

Hopefully you solved your engine problem.

I inadvertently forgot to fully clip in the “deadman” clip once and lost an outing fussing about.
My error but not forgotten!

Let us know how things worked out.
It might help others.

[tegwilym]

Ha! I've done that before on our Bayliner with the deadman clip pulled out accidentally. We figured it out and saved the day, but made me feel stupid, but more knowledgeable at the same time.

The boat went into the shop down near Green Bay. We finally found a place that would work on the Suzuki so we dropped the whole thing off last week. They had to order a few things for the high pressure pump and some adjusting needle. I forget exactly what. It should be ready later this week. Fingers crossed that it runs ok now. I refuse to go out with a questionable motor - even if this is a sailboat also.

Tom

[richter372001]

You should hear a buzzing noise as the pump activates.
Have you checked fuel injectors, though?
Lastly, try bypassing the filter separator, and feed the fuel line directly from a canister.

Good luck!

[vkmaynard]

Our DF90A motor failed this weekend due to bad 2yr old gas stuck in the system. Would not start after running for a few minutes. Could hear the fuel pump key on. Replace by me 2 years earlier.

Easy to diagnose. There is a drain screw on the high pressure sump which is underthe plastic intake manifold on the right side. Check for fuel by opening to drain. We had none. So pulled the low pressure feed tube and blew into it. Total clogged. The float valve was clogged with debris. Finally got it loose enough to where you could blow air thru. Reassembled the sump and motor. Started up.

Lesson learned. Not good enough to simply drain the sump. Need to pull drain on the low pressure filter and drain the feed hose.

Victor

[tegwilym]

Good tip to remember for storing it for the season. I did get ours running (I think - still have yet to get it in the lake and try for real), after $700 for repairs, then another trip back to the shop with the lower unit when I found it was full of more water than fluid. This boat has a lot of proving to do, right now I hate the thing, but will try to clear my mind when we get it in the water - hopefully this year.

[OverEasy]

Hi Tegwilym

Just out of curiosity… What year of manufacture is your DF50?

We can feel your pain, especially having spent a considerable amount of time working through our own engine problems on Over Easy.
We made do with what we had and gradually improved the performance of a 20 year old Tohatsu to about 80% and had fun along the way.
Our next step is hopefully a new engine for our cruising plans next year.
(Parallel to that is a rebuild of the carbs and fuel pump which will bring things back to 90-100%. TBD on what we will do with a spare 50 hp engine… )

We can fully agree with you about having a reliable engine.
We wouldn’t want to be docking in a marina via sail power alone…. We’re just never gonna get that good

Best Regards,
Over Easy

[tegwilym]

The one we have is a 2005 - same as the boat. It indicates it has about 380 hours total on it, so probably not bad since it is a sailboat.
We finally got the thing in the water yesterday after a frustrating setup - a topic for another group!
The motor did stall a couple times, but I think it wasn't totally warmed up enough yet. It did run very nicely after that and we got back to the dock with no problems.

Tom

[OverEasy]

Hi Tegwilym!

Glad you got out on the water!
My personal startup in the morning is a bit hit/miss…coffee…maybe another cup…hmmm….maybe another cup….maybe open both eyes…

[vkmaynard]

Our DF90A started to stall out moving in and out of gear. Finally would not start. Take it out of gear then ran smooth up to 2500+ RPM. Lower to idle then quits.

After studying the problem determined to most likely be the Air Idle Control Valve. Plenty of people complaining about this online. Bought a $18 version on Amazon to test tonight. Will keep one in the tool bag if it works along with a Ebay knockoff $35 fuel pump (currently using). Super easy to replace.

Victor

[vkmaynard]

The IAC was the problem. Purchased an OEM Mitsubishi replacement from Autozone. $147 vs $338 from my local Suzuki dealer where I purchased my DF90A. Abbout a 15 min job to install. I replied on this helpful thread with my findings. https://www.thehulltruth.com/boating-fo ... kes-9.html

Victor