Loss Of Power At 2500rpm

[Lewis]

G,day Raiders,

I am having problems with my 60hp mariner 2 stroke,runs fine up to 2500 rpm, then when open throttle it kind of boggs down when under load. I am putting in for service, but can any one enlighten me as to the likely cause.

P.S. have been doing a bit of trolling lately but plugs are clean.

If there is a cause that can be managed, any advice would be appreciated.

[Sharky]

Im no expert but I think your power band timing may be plying up. The service should answer all your questions.

[Lewis]

Thanx Sharky.

I didnt think it would be anything to serious.

Cheers!!!!!

Edited March 17, 2006 by Lewis

[Bluewater]

Could be one of many things, most likely electrical. I had a friend who had the same problem, ended up being a faulty plug.

Let us know how you go....

Bluewater

[cagedbush]

Had a problem like this with my 40 Johnno.

Throttle advance linkages had become unclipped and wouldnt allow much to happen over that throttle range. If you want to check it look under your flywheel and move the throttle. You should see if it is pushing a secondary unit around under the flywheel once a certain amount of throttle is used.

[Outnumbered]

Had a problem like this with my 40 Johnno.

Throttle advance linkages had become unclipped and wouldnt allow much to happen over that throttle range. If you want to check it look under your flywheel and move the throttle. You should see if it is pushing a secondary unit around under the flywheel once a certain amount of throttle is used.

identical thing happened to my 115 johnno, the plastic socket that the plastic ball sits in broke.

$2.15 and 10 minutes later it was all better

[cagedbush]

We headed home under auxillery power until we spotted the dislocated linkage. Happened again one day when we dropped off a wave. Lucky it never happened in the middle of a barway

[merlin]

I had a similar problem with a 60 hp Yamaha which was caused by sand and gunk after I trolled in some very muddy conditions. (Also I'd left it for a while , couple of months after that particular trip)

Motor would start perfectly then shake rattle and roll when I got the revs up. I thought it was stuffed but the guy at the repair shop cleaned it out and it goes like new.

[Lewis]

Good on ya fellas,

Thanks very much for all your replies. I will definately check the throttle linkage, as I would never have thought to look there. the motor does idle pretty well with only a slight miss when cold, but you know how it is when something goes wrong you instantly start trying to calculate the dollars its going to cost and dont think of the simple things.

[Guest bluecod]

Lewis,

Is it normally aspirated [carburettors] or fuel injected ?

The throttle linkages could be the key, but it could also be the idle adjustment screws having vibrated out of synch particularly if, as you said, you've been doing a bit of trolling.

I had a similar problem a month ago with my 50 Yammy [triple carbs] it would idle fine and get along at about 2500 rpm then die when I went to open it up. I fiddled around with the idle adjustment for each carby, removing one spark plug lead at a time [while working on a different cylinders carb] so they were running at the optimum. Put it back into the water the next weekend and no more problem.

[Lewis]

Cheers Bluecod.

" naturally aspirated " This is great information guy's as it allows me to put together a trouble shooting check list

and offers me questions to ask when I go to get the motor serviced. Thanks so much.

Edited March 24, 2006 by Lewis

[novice]

I have had similar problems with my 40 Mariner.

The first time it happened, the power kept dropping, just when you needed it.....trying to

keep up with the swell coming back in to broken bay....not a pleasant feeling.

This was blamed on the "float valves" ???? needing adjusting.

18 months later, over x-mas of all times (no mechanics were open), the linkage popped. Same result as

a few other raiders....bugger all over idle speed.

Got if fixed soon after and was travelling over lake macquarie, beside the brother-in- law's jet ski at 74kms.

goes well now.

shouldn't be too $$$ to get fixed.

I took mine to Family Boats in Blacktown. They were A++++

Good luck with it.

[Lewis]

Thanks Novice.

I should be picking the boat up from the workshop Wednesday, after speaking with the mechanic when I dropped it in for the service he suggested that it was probably a fuel problem, fingers crossed and not too many $$$$$ later.

Cheers raiders!!!!