Noise & loose of power + dies when rev up slowly

[DavidP]

Hi,
I bought last year a Regal with a 2003 3.0 Mercruiser / 135 HP engine. Soon the engine developed the following behaviour: when I rev up slowly it died. Was good when done fast. In idle it was like "pumping" w/o dying or at least seldom when running for a while.

This year I brought it to a dealer to get a 50 h service done but afterwards this behaviour was still there. In addition I have now every once in a while (but still seldom) a noise like if air would be escaping in a small explosion and I would have for a short moment afterwards a loss of power. This would take approx. 1 sec. and afterwards everything is fine again. This happened so far only when I was higher then 2500 RPM. I could not find anything strange around the engine but I'm not experienced with engines. I had gas in the tank w/o any stabiliser for around 10 month. Could this be a reason for at least my problem with the loss of power? Should I first take out the existing gas before I continue to check? While the service I got a new exhaust elbow because the old blow out and I was driving for a while with the bad ones "fixed" with duck tape. Some water did spray around in the engine compartment. Not sure if this could have caused any damage.

Any ideas how to tackle this and where to start looking?

thx,
David

 

[DavidP]

Re: Noise & loose of power + dies when rev up slowly

Hi,
OK I went ahead and emptied the tank even if I used it twice till I noticed above mentioned errors till half was empty. First through the normal gas fill opening with a long hose and then I removed the hose from the fuel pump to get the rest out of the tank. I added some carb cleaner which also binds water (dry gas) to the fuel and will run it this weekend to see if there are some improvements.

Besides that I will prepare myself to check sparks / compression. Is a flusher like http://www.iboats.com/Seachoice_Motor_Flusher/dm/*******.796386572--keywords.flush--list_time.1218229526--**********.445141716--view_id.4613 enough to provide water to the engine for cooling while running? Anything else or a cheaper one I could use for the same? As long as I don't put it in gear I can leave the outdrive up (out) while running the engine, correct? How about leaving the prop on if I ensure / secure the area around it to ensure nobody can go there?

thx,
David

 

[Don S]

Re: Noise & loose of power + dies when rev up slowly

Do you also have any dieseling or hard starting (cold or warm engine) problems?

 

[DavidP]

Re: Noise & loose of power + dies when rev up slowly

starting is normal. just need to push the lever to 1/4 or give a short additional push and she is up&running. Need to keep it to 1/4 for a short while

I'm not sure if I have dieseling. seldom when I turn her off she was running for a couple of seconds but I always thought it was because I hadn't stopped the boat and the propeller was moved by the water flow causing the engine to run for a very short time.

thx,
David

 

[Bondo]

Re: Noise & loose of power + dies when rev up slowly

As long as I don't put it in gear I can leave the outdrive up (out) while running the engine, correct?

No,.... Lower the drive down to atleast the Trim range.....

Everything inside is Still turning,... The U-joints will be Trashed in No Time if you run it in the Full Up position....

 

[sarantis]

Re: Noise & loose of power + dies when rev up slowly

Do you also have any dieseling or hard starting (cold or warm engine) problems?

May somebody explain me what is dieseling?

 

[DavidP]

Re: Noise & loose of power + dies when rev up slowly

till Don posted the question I was also not aware what dieseling is :redface:
I found this link explaining it http://en.wikipedia.org/wiki/Dieseling

Basically it means that the engine continues to run for a short while after you stop the engine. Even there is no spark the fuel / air mix will be ignited by a hot area in the cylinder

cu,
David