Suzuki DF2.5 issue

harvey38

harvey38

Well-Known Member
Joined
27 May 2008
Messages
2,137
Visit site
Hi all,

I have a three year old four stroke 2.5 Suzuki that I flush and run dry of fuel after each use, it is stored on the rail of the boat in a custom made, breathable cover. I came back to the boat, put it on the tender after a four week break, there is absolutely no compression, having checked the spark plug is tight, still nothing.

A Google search indicates a bent valve or corroded valve seats but I find it difficult to believe when it has never missed a beat and no issues four weeks ago. It's in the boot of the car ready to go to a repair place near us in Staffordshire.

Has anyone else experienced similar issues?

Thoughts, comments welcome.
 
How did you test the compression? Spark plug out and thumb over the hole as you turned it over or a pressure meter? It's a bit of a mystery and I'd be interested in the post mortem!

My own four stroke 2.5 Suzuki has only given me a problem once. I routinely drain the carb after each (very intermittent) use, but after a sojourn of over a year, the little petrol left in the tank had left a thick brown residue to sink down into the feed tube to the carb. Once flushed through the carb with fresh fuel I was good to go. Now I open the fuel and let everything drain out through the carb if it's going to be left idle for any length of time.
 
Neil said:
How did you test the compression? Spark plug out and thumb over the hole as you turned it over or a pressure meter? It's a bit of a mystery and I'd be interested in the post mortem!

My own four stroke 2.5 Suzuki has only given me a problem once. I routinely drain the carb after each (very intermittent) use, but after a sojourn of over a year, the little petrol left in the tank had left a thick brown residue to sink down into the feed tube to the carb. Once flushed through the carb with fresh fuel I was good to go. Now I open the fuel and let everything drain out through the carb if it's going to be left idle for any length of time.
Click to expand...
Nothing technical, I just put my thumb over the hole, no point going any further as I'd be surprised if the pressure (or lack of) would even register on a meter.
 
harvey38 said:
Hi all,

I have a three year old four stroke 2.5 Suzuki that I flush and run dry of fuel after each use, it is stored on the rail of the boat in a custom made, breathable cover. I came back to the boat, put it on the tender after a four week break, there is absolutely no compression, having checked the spark plug is tight, still nothing.

A Google search indicates a bent valve or corroded valve seats but I find it difficult to believe when it has never missed a beat and no issues four weeks ago. It's in the boot of the car ready to go to a repair place near us in Staffordshire.

Has anyone else experienced similar issues?

Thoughts, comments welcome.
Click to expand...
If you are absolutely sure about the lack of compression maybe a stuck valve. Take the cover off and check. .


.
 
Last edited:
harvey38 said:
Hi all,

I have a three year old four stroke 2.5 Suzuki that I flush and run dry of fuel after each use, it is stored on the rail of the boat in a custom made, breathable cover. I came back to the boat, put it on the tender after a four week break, there is absolutely no compression, having checked the spark plug is tight, still nothing.

A Google search indicates a bent valve or corroded valve seats but I find it difficult to believe when it has never missed a beat and no issues four weeks ago. It's in the boot of the car ready to go to a repair place near us in Staffordshire.

Has anyone else experienced similar issues?

Thoughts, comments welcome.
Click to expand...
May be silly to ask. But is the pull cord actually turning the engine?
 
I had this happen in an old car once. Turned out that because it hadn't been started for a few months, the oil hadn't circulated around the engine, and hence there wasn't a proper seal between the piston rings and the cylinder. Simply cranking the engine for a few minutes did the trick. (Of course we only discovered that after removing the cylinder head.) Might be worth pulling your starter cord for a few minutes with the fuel off, to get the oil flowing.
 
Another cause of low or no compression is bent conrod caused by hydraulic lock from oil getting into cylinder during handling.
Was the first pull of the cord harder than usual?
I notice this after my DF2. 5 has been laid (correctly) on its side for a time.
 
DOILY said:
Another cause of low or no compression is bent conrod caused by hydraulic lock from oil getting into cylinder during handling.
Was the first pull of the cord harder than usual?
I notice this after my DF2. 5 has been laid (correctly) on its side for a time.
Click to expand...
No, no compression at all. I always pull the cord out slowly until I can feel compression then give it a good tug with the kill cord removed to draw the fuel through then repeat and it always starts on the second pull. I was convinced someone had removed the plug as a joke but it's immovable once I put the cover on and chain it to the mount.
 
I removed the rocker cover and found one of the valves wasn't fully closing and I suspect it's bent as it is tight in the valve guide. It's now with a local repair shop and see what other damage comes to light when the head comes off!
 
I have a df2.5 and had a sticky valve after running on the wrong fuel (avgas, dont ask), when a valve sticks the pushrod drops into the sump as it comes off the cam lobe.
They can be fished out with a magnet on a stick but attach it firmly or you'll end up with a magnet in the sump too.
Rocker cover off will give it away.
 
snowbird30ds said:
I have a df2.5 and had a sticky valve after running on the wrong fuel (avgas, dont ask), when a valve sticks the pushrod drops into the sump as it comes off the cam lobe.
They can be fished out with a magnet on a stick but attach it firmly or you'll end up with a magnet in the sump too.
Rocker cover off will give it away.
Click to expand...
That, apparently is exactly what happened according to the folks who have it for repair. 4 hours labour plus gaskets and it should be good to go. I run it on regular unleaded so not a clue how it happened.
 
Can be caused by oil in combustion chamber causing it to hydraulic, rocker adjuster coming loose or running it on poor fuel causing detonation also causes valve issues.
DF2.5 Suzukis are the most difficult engines to rebuild. Push rod cups are unbelievably difficult to locate
 
You must log in or register to reply here.

Share this page

Top