Outboard water pump problem

[Sciurus]

Hi

i have recently acquired a Suzuki DF4 outboard, 4hp and 4 stroke)

It started easily but the water tell tale only ran for 15 secs and stopped and the engine started to overheat.

I changed the impeller and gasket, but the problem remains. (There was nothing wrong with the old impeller either).

However, if I remove the rubber cap in the leg ( to adjust the gear stick link) and run the motor,  the Tell tale flows wonderfully!

This implies to me that the exhaust gases in the leg somehow overpowers the water pump pressure, which is released when the rubber cap is removed.

I should add that if I connect a hose to the inlet pipe, the water flows freely, so there is no blockage. The engine has only been used on fresh water.

Any ideas on the fault and how to cure it?

[johnphilip]

1 hour ago, Sciurus said:

Hi

i have recently acquired a Suzuki DF4 outboard, 4hp and 4 stroke)

It started easily but the water tell tale only ran for 15 secs and stopped and the engine started to overheat.

I changed the impeller and gasket, but the problem remains. (There was nothing wrong with the old impeller either).

However, if I remove the rubber cap in the leg ( to adjust the gear stick link) and run the motor,  the Tell tale flows wonderfully!

This implies to me that the exhaust gases in the leg somehow overpowers the water pump pressure, which is released when the rubber cap is removed.

I should add that if I connect a hose to the inlet pipe, the water flows freely, so there is no blockage. The engine has only been used on fresh water.

Any ideas on the fault and how to cure it?

Are you using muffs or a tub of water 

[Mice!]

One of the lads in work is in to his boats and engines I'll ask him tonight. 

[Sciurus]

John, I have tried it on the water and in a tub.

When  I used a hose, I took the bottom of the leg off and pushed a hose onto the rubber seal which fits onto the narrow inlet pipe, so no muffs.

Kev- 👍

I did call into the local Suzuki Workshop and asked the mechanic, he was flummoxed and thought a gasket between the head and leg might have failed (I suppose this means the water pumps straight back into the leg along with the exhaust) however why removing the rubber grommet should make the water flow again, is abit of a mystery. Unfortunately theses gaskets are very pricy and labour is £60 ph...

[foxbasher]

Have a look at the gasket in the impeller housing that seals around the drive shaft. I had an older dt6 that had a similar problem, in the end I had the recess in the housing machined a little deeper so I could press in two seals one on top of the other. 

[Vince Green]

This is why I am still using a British Seagull. Outboards are the worlds most expensive nightmares to fix. If I had my time over again I would be an outboard engineer and practice sucking my teeth while shrugging my shoulders and shaking my head at the same time.

A friend of mine bought a canal boat, it had an outboard as a back up. An oldish suzuki  but she thought she should get it serviced because the main engine was a 50 year old BMC 1.5 diesel and you never know.

She was quoted £2400 by some outfit at Teddington to service it so you can guess her answer was two words, second word was off. They wanted to charge her for inspecting it so she never ever even got it back.

 

Edited May 27, 2021 by Vince Green

[Saltings]

ok if the pee hole works at first then doesnt with exhaust smoke or hot air i would say head gasket gone    despite whats coming through the leg the impellar is working    the pee hole is when the water jacket is full         head gasket fail  you have high pressure gasses pushing back   hence water in the leg overheating no piddle     they are easy to work on    i shouldnt doubt tutorials on u tube on how to   if bolts are coroded  steel to alley you will need a stick welder jab it on the bolt not arc so reddens up  then remove  without snapping    better than oxy acetylene       if you fancy sorting yourself you can pm your number and ill walk you through as you are about 3hrs from me        happy to help

[Sciurus]

22 hours ago, Saltings said:

ok if the pee hole works at first then doesnt with exhaust smoke or hot air i would say head gasket gone    despite whats coming through the leg the impellar is working    the pee hole is when the water jacket is full         head gasket fail  you have high pressure gasses pushing back   hence water in the leg overheating no piddle     they are easy to work on    i shouldnt doubt tutorials on u tube on how to   if bolts are coroded  steel to alley you will need a stick welder jab it on the bolt not arc so reddens up  then remove  without snapping    better than oxy acetylene       if you fancy sorting yourself you can pm your number and ill walk you through as you are about 3hrs from me        happy to help

Saltings , I think you are on the right track. When I talked to the Suzuki engineer (without him seeing it) he was generally stumped but the only conclusion he could come to was cylinder head gasket or the gasket between the head and the leg. Certainly, the problem is pressure related. The Suzuki manual is very good. Now that you have narrowed down the problem, I’ll read up on cylinder head removal and check YouTube. Although, the motor is 15 yrs old, it has only been run in fresh water, so hopefully no corrosion on cylinder head bolts. I’ll get back to you if I have a problem.

Thanks everyone for their contribution.