F-2 Speedy

iTrader: (6)

Hook a scanner to it and see if its throwing any codes

Turbojack

Replace Distributor cap and rotor.

Every time a friend of mines boat will not have the power to plane out he pulls out new cap and rotor, raises hatch, change out and we are on your way again. Over the last 15 years it has happen to him about 5 times, I have been with him 4 of the 5 times it has done it. I try to get him to change out first of year but he waits to do it when it fails.

Brandonb_05

Put a new engine in it.

BUP

iTrader: (9)

Can not fix a motor without knowing what exactly 502 set up you have here - year model would help and engine serial number is needed. VST or cool fuel - MEFI 1 or MEFI 3 - stock set up or not - Stock ECM or retunes - stock fuel set up up or not - stock ignition set up or not. What max rpm can be reach with your app running under load ? What do you have - lacking way too much info here to even pin point an area of what might be the issue(s).

Fuel sample taken from filters and the gas tank ? Check and or Change the distributor cap and rotor - check fuel pressure readings at idle speed 2 k and 3500 and wot if possible can reach those rpms and scan the engine ? Compression test ? spark plugs examined ?

Dart throwing contest without knowing what you evactly have here- and no testing specs as of yet nor what has been check and ruled out - Just saying

92nsx

Way to many fat fountain skanks on board ??

cong95

I was able to hook it to a computer last night and the ECM showed no codes! The boat sounds like it always has, all gauges are at normal levels just flat won't get above 2k rpms when trying to plane out.

cong95

It's a 2000 502 Mag mpi, mefi 3 I believe (10 pin) with Arizona Speed tune. MSD ignition. Other than that pretty much stock with just under 400 hours.

3pointstar

I have to throw in my two cents

1. Did anything happen to the throttle cable- Are you sure when you give it the gas that you really are giving it the gas?
2. YEARS ago- and remember I am NOT a mechanic. I had a Chevy Nova- I changed the oil - the car started just fine but when I drove it around the block - I couldn't get it over 30 mph-- it was horrible - No backfire-- we tried everything under the sun thinking it was a fuel issue. WRONG. When I took the oil filter off I must have bumped the distributor and knocked it out of time. Put the timing light on - readjusted and all was well in Heaven and Earth.
3. We had a coupler go out a couple of years ago- Engine ran fine - but when it went out the boat started to get slower and slower

Just some thoughts

Please keep us informed-- I want to know how this story ends.

All the very best

3pointstar


Just offering

1989mach1

Earlier this year this happened to me with one of my motors. What happened to me was I had my son in there cleaning with Windex and he bumped the air fuel sensor and unplugged it. We went out for a run and the starboard motor would not go over 2k and couldn't get on plane. Found that is was unplugging and plugged it back in and good to go.

cong95

Thanks for all the advice! I found the problem...loose spark plug wire and one fouled plug! Thanks again everyone.