overheating outboard - half blocked waterways

Modulation

Modulation

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Ok so I didn't follow the advice on winterisation of my Suzuki 2 hp outboard properly - never flushed it through with fresh water. So over the years the impellers are not able to pump so much water through and now every 20 mins or so the engine stops and needs 10 mins to cool down. Then it restarts fine. And the cycle repeats itself.
I know that furring up the waterways is potentially terminal but given that some water is still going through, does anyone have any ideas on how to rescue this engine? I don't want to replace it as it weighs only 21 lbs and all the new ones are a lot heavier.
 
Remove cylinder head, scrape out all of caked salt from head and liner, fit new gasket and run in some fresh water, Should be ok after that.
 
Fernox DS-3 is a sulphamic acid based descaler.
Fernox DS-40 is an organic acids based descaler.

DS-3 will probably be the quicker acting of the two

Fernox SUPERCONCENTRATE SYSTEM CLEANER is another acid based cleaner.

All should be readily available from decent plumbers merchants and DIY stores.

There are of course other brands available but an acid based descaleror cleaner is what is required.

A new pump impeller in addition to the descaling if it has not been replaced within the last 3 or 4 years
 
You should ensure the pump is working correctly first. Either by replacement or ..... On my old Johnson with the pump bottom end removed I can attach a garden hose to the tube running up from the pump into the engine. This seems to simulate the pump quite well. If there is a blockage then there is no water at the tell tale but if no blockage water runs well out of the tell tale and also into the exhaust tube.

I would suggest that you remove the cylinder head and also if it has one the thermostat housing to clear any blockages. This might seem severe dismantling but in my experience the primary cause of terminal death of outboards is the corrosion of SS bolts into the Al castings. So the sooner you get the bolts out and lubricated the better.

If any bolt is totally seized then try heat. But if that fails then give up dismantling, try Fernox etc and just accept that you will have to either risk snapping the bolt off in the future and or throw the motor away. Definitely DIY your engine. The proffessionals are all too quick to condem an engine because of labour costs. good luck olewill
 
Why mess around with it? Trade it in against a new Suzi 2.5 4 stroke, cost me under £250 to change mine this year with the trade-in on my old Suzi 2.2. Ok it's a bit heavier, but I don't notice because it has a proper carry handle. Plus it has a neutral gear, twistgrip throttle, it's quieter, and it's more eco-friendly (apparently, whatever that means) My 'best buy' of the season!
 
First, make sure that some water is getting through. If not, then check the condition of the impellor and replace if necessary.
If no water and the impellor is good, then a strip-down to clean out the waterways will be needed.

However, if some water is getting through, then run the engine up in a tank of rainwater (rainwater is ever-so-slightly acidic). Remove the prop if necessary. To speed up the process add 100 g or so of citric acid (ex home-brewer's supplies) to 10 gallons of water, or use a standard kettle de-furring product. Flush well afterwards.
Colin
 
Rydlyme

After a recommendation on this forum a year ago, I bought a bottle of RYDLYME from my local chandler (Seamark Nunn).They use it to flush out their outboards - they are service agents for Mariner and Suzuki outboards.I did same on mine and the result was a 100% improvement in flow rate.Highly recommend the stuffNo connection.
 
If the bolts, if any, do shear take the engine to a freindly 'engineer' Drilling out the old stud and re-threading is something they are used to. I took my Malta to a friendly lawn mower man who did this for £15 late last year.
 
Have just done this job on 2 Suzuki DT2's so I know what is involved.
The headgasket is about £11. The 4 studs holding the head on will most likely be seized- suggest penetrating fluid left overnight and then a few stiff blows with a soft faced mallet onto a 10mm socket/extension bars.
Loosen each nut by a 1/4 of a turn in a diagonal sequence. If the bolt feels like its going to shear off STOP, respray with penetrating fluid and DO THE BOLT UP a 1/4 turn. Repeat the loosen, penetrating fluid, tighten then loosen sequence as much as necessary.Its not always the thread that seizes, it can be the clearance between the head bolt and the head itself.
When you do get the head off, you'll find that the waterways around the piston liner will probably be completely jammed up with salt deposits and crud. I used a Dremel type tool with an engraving bit on, to get rid of all the deposits and flushed all the rubbish out with carburettor cleaner. Do the same on the head casing and ream/drill the stud holes to 6.5mm to remove corrosion.
I also removed the 6 nuts where the crankcase joins the shaft casing and cleaned this area out. This gives access to the water delivery tube, which can be cleaned out with a length of stiff wire.
Prior to reassembly, use a tap (6mm x 1.0mm thread) to clean the bolt holes out in the cylinder casing and clean the head bolts with a die (or replace them)
I used Wellseal STAG jointing compund on all surfaces prior to reassembling the joints (even on the head gasket)
Possibly not the done thing, but I applied COPPASLIP to the thread of the headbolts, but I always do use it to aid remoavla in the future.
Head bolts should be tightened in steps,horizontally, about 2lb/ft per step up to a max of 10lb/ft.
Run engine to temperature looking for leaks prior to putting on th ecasings.
BTW the 2 Hp headgasket is no loger availble, but the 2.2Hp is identical!! If you need the part no. PM me.
 
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