Problem under load

Dan · 02-08-2011, 07:24 PM

Hi All,
I've just finished the final peice of the bernico that being the engine.
I had a couple of issues starting yesterday but have now overcome this, turned out to be mostly down to me and the fact the engine's been stood for some time.
Anyhow, I set off to the slipway today for the first "real" usage only to have a problem when under load. As soon as I put my foot down I cant get the thing to go, it revs up to around 3.5k but will go no more. Yet in nuetral it now sounds sweet as and will rev with no issue's. It not bogging down and doest feel like its will pass through and then go, its just sticks to around 3.5k and its obvioulsy sounds down on power. I pulled it back on the trailer, trimmed it out and started in gear, almost under 1/2 load as I could see the tips of the prop, reved to 5k and trimed in at the same time. As soon as it comes under load it simply will not rev.
I have a couple of things in mind but will throw it out to the masses and see what people thing.
For info its a merc f1 head (known to be in v good condition), lighting ET, engines low as it will go and its on a f2 bernico, spark on all 6, injectors have been cleaned, all new lines and filters.

Hydrostream · 02-08-2011, 07:55 PM

have you tried a different stator?

also, maybe check fuel pressure

Wacky Racer · 02-08-2011, 08:31 PM

as above, sounds like stator

Burty · 02-08-2011, 09:40 PM

Quote:

Originally Posted by Hydrostream

have you tried a different stator?

also, maybe check fuel pressure

Quote:

Originally Posted by Wacky Racer

as above, sounds like stator

Ph@ntastic · 02-08-2011, 10:53 PM

Bad coil ?

OCRDA · 02-08-2011, 11:21 PM

What size is prop ?

Dan · 02-08-2011, 11:42 PM

Quote:

Originally Posted by Burty

Looks like your soon be whipping yours off then

Quote:

Originally Posted by OCRDA

What size is prop ?

Lightening et , 22 i think

stormin177 · 22-08-2011, 12:29 AM

Had a very simular problem a few years ago and it was the fuel regulator not holding pressure in fuel rail, would rev up out of gear once in gear it would
Rev up like it was going to go then just droped all it's revs.

Dan · 22-08-2011, 09:00 AM

Quote:

Originally Posted by stormin177

Had a very simular problem a few years ago and it was the fuel regulator not holding pressure in fuel rail, would rev up out of gear once in gear it would
Rev up like it was going to go then just droped all it's revs.

I'll fit the fuel pressure gauge this week as I've changed the stator and its still the same.

FrenchPhil · 22-08-2011, 11:18 AM

Mine does that when it's cold & takes a while to rev up. Could it be a heat sensor problem ?

Dan · 22-08-2011, 12:19 PM

Quote:

Originally Posted by FrenchPhil

Mine does that when it's cold & takes a while to rev up. Could it be a heat sensor problem ?

I dont think so tbh, the engine had been running for a little while. I'll put the pressure gauge in this week so I can cross that off the potenial list, and also put a set of spark testers on and try again so see if I have a coil breaking down underload. I have a couple more things to try before I give us totally with it.

Ph@ntastic · 22-08-2011, 01:04 PM

My gues still is one of the coils , i think one is defect all the time not only under load .
As long as there is no load it will rev. fine but when there is a load it wont rev. same problem i had back then .

Dan · 22-08-2011, 01:28 PM

Quote:

Originally Posted by Ph@ntastic

My gues still is one of the coils , i think one is defect all the time not only under load .
As long as there is no load it will rev. fine but when there is a load it wont rev. same problem i had back then .

Hopefully, once I've got my hands on the testers I'll run it under load on the trailer so see what it highlights or doesnt if you know what I mean.
I did check each plug for a spark against the block one at a time and did seem to have spark on all 6 but as you say this was not under load.
Fingers crossed. Never know, might have it ready in time for the winter!