Logo
FULL SITE MENU

98 DT115 Runs ok. Cuts out. Starts again. Cuts out.

I

Ianeye

New member
Hi All,

The boat went in a couple of weeks ago after winter lay up. We had one trip out with no problems.

The other day, we went out fishing and the motor ran fine. Then after a drift we were motoring to reposition at about 3000rpm and the revs suddenly started to drop and kept dropping until she stalled (over about 10 seconds). When we turned the key it started, weakly, but it got going again. We turned to head back to harbour and the same thing happened. She ran for a little while then the revs dropped. I gave the primer bulb a few more squeezes and she restarted and managed to get back to our berth. We checked the fuel vent and connections to the tanks but the engine ran fine. We went back out for a test run and she ran perfectly fine for 30 minutes.

Chalking it up to maybe the vent being caught or something we went back out today. After about 40 minutes of boating the same thing happened. We took the hood off and noticed the small clear fuel filter/cup was leaking slightly when we squeezed the primer bulb. I reseated it and the leak went away. We tried our other petrol tank. She started, ran and then died again and this time she would not restart so we headed back in on our auxiliary.

Back in harbour we tried checking the fuel line as far as the vapour chamber. That was full. Checked over all the electrical connectors. I tried turning the fly wheel with my thumb in the gap in the cover. It moved. She still wouldn't start.

After about 30 mins I tried one more time for luck and she started straight on the key. Ran at idle for 15 mins. Stopped, started. all fine.

A few things to note:
-We changed the impeller over the winter. The tell tale is flowing fine and water is coming from the discharge port.
-We replaced the oil filter/sensor as in the past we had problems with an oil flow alarm. The bullet connector disintegrated when I went to disconnect it and so I replaced the connector and the part. This is connected the right way round with the arrow pointing towards the hose that goes to the pump. She seems to be moving oil and we haven't had the flow alarm since replacing the filter/sensor.
-I replaced the needle valve in the vapour chamber. When we bought her last year, the old one was sticking and we had to have it ultrasonically cleaned. I found a new part on ebay and fitted it.
-Last year we replaced the low lift fuel pump as the regulator was leaking. This appeared to be running fine today.
-We replaced the bottom spark plug as it was a little corroded. The whole set was changed last year.

So, any ideas what this issue could be? A friend has suggested testing the injectors...

TIA
 
racerone said:
A 1998 model DT 115 is shown to have carburetors.----Why would your friend suggest injectors ??
Click to expand...
Hi racerone.

Sorry, I should have mentioned. The year stamped on the engine is 1998, and it was first used in august 1998. But the serial number is 11503-971001 which is shown as a 1999 model. Not sure why the discrepancy.
 
racerone said:
A 1999 is also shown with carburetors.
Click to expand...
On the parts diagrams on Brownspoint the schematics show carburettors in models up to 1997. This definitely has fuel injection. Unfortunately it looks like fig 7 is missing on their database.
 

Attachments

  • IMG-20240420-WA0009.jpg
    IMG-20240420-WA0009.jpg
    78.6 KB · Views: 5
df40-mechanic said:
highly unlikely that all injectors fail simultaneously. Have you checked your high and low pressure fuel pumps, fuel filters etc?
Click to expand...
This is what I thought.

We've checked the the fuel line from tank all the way to the high pressure pump and it all appears to be working ok. The filter had a few bits in it but nothing remarkable. I did take out the top two injectors which are easy to access and they appear to be in good condition. I've ordered a new diaphragm set for the high pressure pump and once that arrives I'll be able to check there. The boat is currently in the harbour and we will have to move her to a different berth to do the work.

Since my original post we've taken her out twice. The first was a test run, spending about 50 minutes on the water, cruising around, stopping, restarting etc trying to replicate the conditions. She ran flawlessly although we restricted running to 3000rpm.

The second time we decided to head out fishing albeit close to home in case of trouble. After warming up and beginning our run out of the harbour, we were at about 2500 rpm when the RPM dropped sharply for about 2 seconds before recovering. It did this once again so we circled back a couple of times. It didn't stall though and quickly recovered. After that the engine ran fine all day although as before, we kept her to roughly 3000rpm

On the run home I opened her up to about 3500 rpm and still no issues. We have noticed that the throttle is a little sensitive and creeps a bit. Also we suspect that the rev counter is not completely accurate (When dropping the throttle it doesn't appear to lose the right amount of revs straight away if you know what I mean.
 
It does sound like a fuel issue. Just wanted to mention that the Suzys have a 3K RPM cutout when they are overheating. They will rev limit to 3K with an alarm. Don't think/know if that applies in your case. This alarm does not clear itself on my model forcing a restart. Good luck!
 
df40-mechanic said:
It does sound like a fuel issue. Just wanted to mention that the Suzys have a 3K RPM cutout when they are overheating. They will rev limit to 3K with an alarm. Don't think/know if that applies in your case. This alarm does not clear itself on my model forcing a restart. Good luck!
Click to expand...

Aye, we had this issue with the oil flow sensor last year. It would kick in randomly every few trips with a buzzer and light. After investigation we found the bullet connector on one of the cable completely corroded (It literally fell to bits just trying to seperate the male and female) so I replaced the sensor/filter and crimped on a new bullet connector.

It's odd that when we get this issue the rev limiter hasn't kicked in and no alarm or warning light has shown. The engine literally just winds down until it stalls.
 
Back
Top