agh confused

[phil-s]

Hi all
I have a BF 20 honda on a 3.9 mt horizon tinnie deep hull version
Lately I have noticed that the engine is down on powerIt used to make
about 18 knts on gps it now stuggles to hold 15 wot. i have noticed now that I have to run with the throttle wide open to travel at a reasonable pace were as
Iused to run at about 3/4 throttle
Recently had a service with carbbie strip an impeller and new plugs and fluids
The motor runs well its quiet no obvious noises it idles very well
it just seems as though it is tired
I have had the motor since 2003 it has been seviced and flushed always
I guess it would have maybe 200hrs on it
any body got any ideas
could it be the prop shrinking or a bush or something

[Jarrah Jack]

I really doubt that its tired after 200 hours. Give it a compression check and it will give you a lead. May be something to do with the recent tuneup. Spaniard King, Gary a member on here is a Honda Mech and should be able to help.

[Noelm]

OK a few possibilities, 1, damaged prop, 2, carbies been done, now not as good, seems to indicate the carbies where not done as well as they could have been, or they are out of adjustment, check to see if the throtttle fully opens the carby butterfly/s, 3, more weight in boat now, some pretty simple things to check there.

[STUIE63]

are the revs the same

[phil-s]

Yeh I just changed out a 100 amphr deepcycle battery for a 18 amp hour
since I don't run a trolling motor
so the boat should be lighter

[STUIE63]

if that yeah is to the revs being the same then I would be having a look at the prop it will either be worn and not gripping the water ( getting more slippage )or the bush is spinning the way to check this is to get a little spot of paint and marl the prop and mark the spline on the bush and take it for a run and see if it has moved

[phil-s]

That is good advice "thanks all" I have spoken to the mech he has said the same;
he did compression, carbs and throttle in the service so thinks it could be the prop
in some way.
1 Does the benifit of repropping with ss justify the expense on small motors and what about the amount of blades ?
2 what about a foil? my understanding is a foil just gives lift with added drag
thanks again guys

[STUIE63]

just make sure that the engine reaches maximum revs when you reprop I wouldn't bother with s/s on a small motor but that is me . I vote a big no for the foil
Stuie

[Roughasguts]

Could be running a tad rich.

Cheers.

[Noelm]

no need to fit a foil, remember it was OK before, something has been "done" to cause this, no amount of accessories is going to fix it, especiially a foil.

[johncar]

Had my Evinrude 115 serviced many years ago and it felt sluggish for a few trips out on the water after.

It was annoying me so I pulled the cover off one day while out on the water with the engine idling I pulled each spark plug lead off one at a time being younger and more stupid.

Zapped myself a couple of times but found one cylinder doing nothing so it didn't make any difference with the HV lead on or off. Anyway there was no power to that plug. Traced it back to a small connector had been dislodged on the LV side of the coil. Plugged it back in and away she went like a rocket again:)

My friends 200 Evinrude had a stalling problem for years after a service but no mechanic could find the problem.
He found it himself one day while investigating something else in the way of an oily residue always leaking from the engine. The main fuel line on the tank side of the pump in the engine compartment was just sitting against the pipe fitting and not attached.
It was amazing that we did countless offshore trips and it ran fine at cruising speed with the pumps suction pulling the rubber tube to seal but come away at idle and suck air. Amazing!!

So I am thing it will something like that, but regardless check all the simple things first, ie fuel lines and al electrical connections.

[Spaniard_King]

Tappets out of adjustment or carby not opening to full throttle assuming the outboard tech is competent

[FishHunter]

The 1st thing I would check is that its actually getting full throttle.