Most common faults on Suzuki 4-strokes..?

[Maninmanaus]

I've run my DF50 from new for around 540 hours (in freshwater). Twice a year-ish I do a long run into remote areas of the Amazon with guests (longest one was 1500km), and I need to try to take along as many spares as practical to cover any eventuality. I thought I was doing fine until recently, when my motor just stopped for no apparent reason, leaving me a seven hour paddle to get somewhere where I could get help. I'm still trying to sort the problem out (thanks to redlowrey for his patient help), and I just wanted to ask everyone - on the basis that many of these engines are fundamentally similar - two things: 1) what they would vote as the most common fault and 2) what would be their hot tips for spare(s) to take along.

For my last trip I carried: low pressure and high pressure fuel filters, oil filter, thermostat kit, oil pump kit, fuel pump kit, plugs, two impellors, 4 props, 1 set of prop bushes, water separator, 1 set fuel injector 'o' rings, fuses, oil, WD40, silicone sealant and tools. None of it did me any good recently, and although I'm not sure what the current problem is exactly, I'm thinking of adding a multimeter, an ECM Main relay, a Starter motor relay, and two neutral switches. I'm also going to take a small back-up motor in future, because being stuck in the Amazon for more than a day or so is torture

The only problems I've had (until now) have been: badly seated 'o' rings on the injectors (courtesy of the local service people - idiots), causing a stall in neutral; worn out impellors (twice), causing overheating; and filthy injectors (common problem here - the fuel is execrable), causing uneven running/stallilng.

Any input would be welcome - the Suzuki people here are useless, and no-one seems to be able to give advice on stuff until something goes wrong (like - after the event - "ah yes- that's a common fault - you should always take a spare impellor" etc). Maybe it would be useful for anyone else contemplating long runs and/or venturing into areas where they have to be self-reliant.

[boats.net]

Fuel issues are always the most common failures, might take spare injectors and the relays are good idea.

[mitch]

if the fuel is that bad a spare high pressure fuel pump

[boats.net]

High pressure pumps do go bad, if fuel is an issue, then yes a spare fuel pump would not hurt.

[JTNail]

I think you really should have a backup outboard engine ! At least better as paddles and even if you take a hundred spare parts with you, you'll see you need a part you didnt take with you

[Maninmanaus]

Originally Posted by JTNail

I think you really should have a backup outboard engine ! At least better as paddles and even if you take a hundred spare parts with you, you'll see you need a part you didnt take with you

Ha ha - ain't that the truth. Problem this time proved to be a neutral switch... Agree on the relays and will carry these in future, but am already on the hunt for that 5hp to hang on the back.

Agree re the fuel pump - I have a repair kit on the boat. Not sure about my ability to do the repair while bobbing about on the river, though...

[Maninmanaus]

Originally Posted by boats.net

High pressure pumps do go bad, if fuel is an issue, then yes a spare fuel pump would not hurt.

Point of interest - here in Brazil, it is a legal requirement that gasoline contain a minimum quantity of ethanol. At present it is 25%, and all car engines sold in Brazil have to be (de-)tuned by the manufacturer to run on the stuff. Not only this, but we are forced get a lot of our boating fuel either from (often illegal) floating petrol stations with dodgy tanks - lots of condensation and worse - or from guys in floating wooden houses who get it wherever they can and store it in plastic barrels. Often the same containers are used for diesel and gasoline. To top it all, I know of one instance where a fuel station in Manaus had a delivery from its distributor which contained a significant quantity of animal fat. I believe Suzuki outboards here are also de-tuned and revs are limited. I know one guy who uses a coffee strainer to strain every drop of fuel that goes into his tank; me, I filter it as it goes in and then have to rely on my separator, plus low- and-high pressure filters, all of which I change every 100 hours without fail. I also have my injectors cleaned every 50-100 hours. So, um, yes - fuel is a problem!

[mitch]

the kit you have would be low pressure you still need a high pressure pump

[kmoose]

The high pressure pump is in the vst tank and is not an "on the water" fix. The magic fix for most fuel related issues with our motors is Seafoam and or Yamaha ring free maintainance treatment of all fuel running through the motors. Stopping the ethanol before it causes the problem is key.... After care cost $$$ and causes problems dificult to troubleshoot for your average service facility.

[Maninmanaus]

Thanks Mitch - looked again at my manual and I see where the HP pump is now. I may buy one to keep with me, although as kmoose says, it's not an easy fix on the fly. I don't think I could do it unless I could get the boat ramped up somehow (not necessarily impossible here).

Kmoose - I can't get Seafoam here, but will try to source some of the Yamaha product - thanks for the tip. I am using an additive already - usually either STP or Bardahl.

Interestingly enough, I bought a new Honda (4-stroke) motorcycle recently (manufactured here) and the owner's manual specifically warns that the engine is designed to run on either pure ethanol or the usual 25% ethanol/gasoline mixture, and you should not under any circumstances use additives. Hmm...

Another point - I found an interesting Yamaha pdf document specifically relating to ethanol (http://www.yamaha-motor.com/outboard...Fuel_Flyer.pdf). Obviously they're pushing their products, but nonetheless they say replace the water separator every 50 hours. At the moment I'm doing this every 100 hours unless I know I have a long trip to do (in which case I just replace everything before the trip, regardless of accumulated hours). Any thoughts on this?