2008 Merc 60/40 Jet 4 stroke EFI loss of power

[lastone2know]

I have a 60/40 jet that is a 4 stroke with EFI. I have had the boat since brand new and ran great the first couple of years I have owned it. At the end of last season I started to notice some loss of power especially the get up and go part. When I first got the boat I could have three people in boat all sitting front and back with me at the console and the boat would plane off pretty easily. Last year I noticed an issue where I would be "plowing" water rather than even attempting to plane I had the motor checked at the local marina and they went over the boat and changed the plugs and did the regular service. He thought it might be an issue with ehtanol in the gas because what I described matches some of the issues he has seen in other boats. We checked and shimmed the impeller so I don't know if it's that. It seems that the motor is lacking. I don't know how to explain it and I don't have a RPM gauge to have a reference. Has anyone seen anything similar to this? I am sure I have missed some details so please feel free to ask any questions. Any help is much appreciated.

Thank you
Dan

 

[lastone2know]

Re: 2008 Merc 60/40 Jet 4 stroke EFI loss of power

After some research I see some people having issues with injectors requiring a cleaning. Anyone see issues similar to this and find an injector cleaning fix the problem? I don't seem to have any issues with idle and running. Engine seems to run pretty good with no sputter at idle or even through all throttle positions. She just seems lacking out of the hole and takes awhile to plane off. Any advice would be greatly appreciated.

Thank you
Dan

 

[PontoonboatFun]

Re: 2008 Merc 60/40 Jet 4 stroke EFI loss of power

if it has a fuel module (container on the front to the engine), it may be a cracked vent hose to the fuel regulator. this allows fuel to be sucked into the intake manifold. Mine lock down with fuel. I have a 115 4 stroke EFI 2007 model

 

[lastone2know]

Re: 2008 Merc 60/40 Jet 4 stroke EFI loss of power

Thanks PontoonboatFun I will check over the whole fuel system and check the lines. I also ordered a new fuel filter etc... It was changed last year but just in case it's a cheap fix if that works.

 

[lastone2know]

Re: 2008 Merc 60/40 Jet 4 stroke EFI loss of power

Here is an update since I last posted. I checked over the entire fuel system and everything seems to be fine, but I am not sure I checked every single connection but I feel I looked over most. I could be missing something small. It doesn't seem like it's starving for fuel or that it's sputtering at all just loss of power. I replaced the fuel filter assembly. I also installed a small digital RPM gauge to monitor the RPM's while I was testing. The max RPM I was able to obtain is 4000 RPMs I tried upstream and downstream in the river and no change either way. I mainly seemed to have held around 3700 occasionally bouncing to 4000 but never higher. Now given this is a RPM gauge that is wrapped around the spark plug wire so I am not sure how accurate this is, but respectively seems to be 1500 RPM's lower than what Merch says the max rpm's can be at WOT which I believe is 5500 RPM's. Would this be a case of clogged injectors etc.. anyone recommend steps to move further?

 

[bilge rat jim]

Re: 2008 Merc 60/40 Jet 4 stroke EFI loss of power

Presuming you have good spark and compression on all 4: Before you go any further, i would suggest you have a dealer scan the outboard. This may or may not cost you a coupla bucks, depending on the dealer. Trying to diagnose this type of problem on an EFI outboard without a scan is like picking fly**** out of pepper while wearing boxing gloves. One thing that comes to mind is a faulty throttle position sensor, but thats only one of about 40 problems that could cause low rpm. I'm leaning toward an electrical/ignition problem.

 

[lastone2know]

Re: 2008 Merc 60/40 Jet 4 stroke EFI loss of power

Bilge rat jim, I just had the boat serviced in the beginning of the summer. They replaced all the plugs and checked compression. Everything checked out ok there. They cleaned the fuel system and changed the oil filters etc... They also adjusted the impeller and checked the pump etc.. At the time I had told him of the issues and he thought it might have been fuel related since all of the issues with the ethanol in the fuels. He suggested I run a couple of tanks of gas with treatment and see if that helps. I am currently on my 3rd tanks since and I haven't noticed a change. I called him back but he is booked til the end of the month so I am trying to work out some other areas on my own while I wait. The other night I was going out to do some fishing on the local lake so I played with the throttle adjustment to see if I could get anymore out of it. I backed the screw out and adjusted the throttle out as far as I could. I am not sure if this would give me anything added but just wanted to make sure it wasn't an adjustment issue. Took it out on the lake and there was no change in performance. I pushed around 3500 RPMs at the max and didn't notice any better take off out of the hole etc.. I can't seem to find a TPS for this year model engine (2008) I can only find up to 06. Is it possible they changed these models? Also is it true with a Jet RPM's wouldn't change as much as they would say a prop motor? I am only curious because a friend of mine said his boat would run lower RPM's with more load or the other way with a lighter load. As I said I am hoping when I take it in at the end of the month they can pinpoint but in the meantime I would really like to get it figured out since I fish about 2 to 4 times a week. Thanks again for everyone's replies.

Dan