Mercruiser 4.3 262 Magnum EFI Gen + Won't Start

[650]

Hello everyone

I have a 1997 shakespeare 650 with the 262 vortex motor
I've only just bought the boat and it ran fine on the test , since then when i put it in the water it started and ran ok until i gave it some beans and it died it started and died every time i pushed the throttle

i had to keep the revs low to get back to the dock ,this problem slowly got worse until it wouldn't even start I did notice the the engine temp didn't move in the 10-15 mins it was running I thought it should have moved a bit could this have anything to do with fuel delivery ?

So here came the search for the engine problem , checked for a good spark which i have , I changed the fuel filter and made sure all the lines were free of dirt i seem to be getting fuel coming out of both injectors but not sure if it's enough as when i spray some more down the intake it fires up , there are two pumps a lift pump and the VST pump they both seem to be working i have even put a prob and gave them a live as i tried to start it , I also checked for compression and there was o on number 2 so i changed both heads that cured that .

But I still have the same problem it won't start unless I pour more fuel down the inlet manifold and it cuts out as soon as i stop. should I check the fuel pressure ?..does anyone know what this should be and the best way to do it ?....

Thanks for reading any help would be greatly appreciated

 

[alldodge]

Hello everyone

I have a 1997 shakespeare 650 with the 262 vortex motor
I've only just bought the boat and it ran fine on the test , since then when i put it in the water it started and ran ok until i gave it some beans and it died it started and died every time i pushed the throttle

i had to keep the revs low to get back to the dock ,this problem slowly got worse until it wouldn't even start I did notice the the engine temp didn't move in the 10-15 mins it was running I thought it should have moved a bit could this have anything to do with fuel delivery ?

So here came the search for the engine problem , checked for a good spark which i have , I changed the fuel filter and made sure all the lines were free of dirt i seem to be getting fuel coming out of both injectors but not sure if it's enough as when i spray some more down the intake it fires up , there are two pumps a lift pump and the VST pump they both seem to be working i have even put a prob and gave them a live as i tried to start it , I also checked for compression and there was o on number 2 so i changed both heads that cured that .

But I still have the same problem it won't start unless I pour more fuel down the inlet manifold and it cuts out as soon as i stop. should I check the fuel pressure ?..does anyone know what this should be and the best way to do it ?....

Thanks for reading any help would be greatly appreciated

:welcome: to iboats

From your testing results sure sounds like lack of fuel. I'm thinking fuel pressure coming from one of the pumps. You have 2 relays, one turns power on to the engine and where you hear 2 beeps when the key is turned to run. The other powers the fuel pumps. Both relays are the same, so if your hearing the 2 beeps, pull both relays and swap their position and see if anything changes.

If there is no change, you need to measure fuel pressure at the lift pump (4 to 7 psi) and the VST (40 psi or so)

:welcome: to iboats

 

[650]

Thanks Alldodge

I only have one long beep that's been the same since the first time i saw the boat .. I'll swap both relays as it's an easy test
and i'll go and buy a pressure tester now you've told me what they should be

I'll let you know my findings thanks

 

[alldodge]

To measure fuel pressure it would be best to get a TBI fitting made by GM. Should also be able to get one of them from an auto parts store. In this link it shows what your looking for and where to attach it
http://forums.iboats.com/forum/engi...97-attempting-to-measure-fuel-pressure-on-tbi

 

[650]

Ok trying to source the test kit with the TBI is proving a little difficult but i think one of the shops in the marina has one but he's away for a few days
I'll reply as soon as i can do the test

 

[650]

Sorry for the delay I still haven't found someone with the right adaptor i'm going to try another marine shop this week and will let you know my finding asap

 

[alldodge]

Sorry for the delay I still haven't found someone with the right adaptor i'm going to try another marine shop this week and will let you know my finding asap

In post number 2 in the previous link

91-806901 has a Schrader fitting

If you google this number you can find the part. If you took the pic of the item to the chevy dealer he should have one on the shelf

 

[650]

I think the problem is i'm in the UK
But i've found someone with one and should be able to test it this week

 

[650]

Ok we have an update we have the right pressure 38 cranking and spiking at 50 when you stop cranking

The marine mechanic said that he had a 502 some time back with the same problem and it turned out to be the small black box that sits in the base of the distributor under the cap with some wires going to it (sorry I forgot what it's called) I take it that it's the electronic points

I have found someone with one of these thats cheap so it's going to be an inexpensive try

What i still don't understand is there is fuel going into the inlet manifold but i pull a plug and it's dry ?

 

[Fun Times]

Ok we have an update we have the right pressure 38 cranking and spiking at 50 when you stop cranking...What i still don't understand is there is fuel going into the inlet manifold but i pull a plug and it's dry ?

The fuel system you have is putting out as high as 50 PSI of fuel when you turn the key on but don't crank the engine over..Correct??? And the only way you've seemed to have found to make the engine run is by adding more fuel down the throttle body?

Something isn't adding up correctly as 50 PSI of fuel is to high for this system.... Your engine serial number would help find the correct fuel pressure regulator specifications.

 

[alldodge]

What i still don't understand is there is fuel going into the inlet manifold but i pull a plug and it's dry ?

Which plug are you removing?

 

[650]

Sorry Fun times no when i crank it it's 38 and as i let go of the key it spikes to 50 just for a split second

And yes the only way i can make it run is to feed extra fuel down past the injectors

we took the reading from in between the vst and pipe number 16

The serial number is 0F803847

Thanks guys

 

[650]

Sorry All Dodge I just read what i wrote what i meant to say was

without me adding any fuel there is still a fair amount going into the inlet manifold when being cranked , but when i take a spark plug out it's dry

 

[alldodge]

Fuel line 16 is the main line feeding the throttle body, so I agree how could you get 38 psi at the TB and have no fuel in the line.

Check the fuses for the injectors, there are two

 

[650]

The only fuses i can see on the motor are up by the ecm on a bracket there are three a 7.5 A ..10A..and a 20A all are ok i didn't see a 16A would that one be somewhere different (I am going on memory now I'm not close to the boat at the moment )

 

[alldodge]

My thought is if its not a fuse then it could be the ECM. When the engine cranks the distributer sends pulses to the ECM, when they are received the ECM then turns the injectors on/off in pulses. So if your getting pulses from the distributer and not to the injectors, it would be the ECM. Need to verify.

Do you have access to an engine scanner?

 

[Tail_Gunner]

https://drive.google.com/file/d/0B3waQufF7aAAQnVaNmlWQUI0Z2s/edit?pli=1

Thats quite a good file follow it close and you should be able to identify your engine...fuel pressure....injector type...fuel type and trouble shooting tree.

 

[Fun Times]

i seem to be getting fuel coming out of both injectors but not sure if it's enough as when I spray some more down the intake it fires up,

Being that it's mentioned that 650 can see fuel coming out of the throttle body injectors "while cranking" (< I'd assume?) wouldn't necessarily be a strong sign of an electrical issue preventing the engine from starting/injecting fuel but anything is possible so don't rule it out on that note. Ensure your battery is producing good battery power and cranking amps that should have a minimum of 750 CCA's. Using a multimeter, you'll want to be sure the power to the fuel pumps are getting full 12 volt power.

Any chance of posting a video of the injectors spraying fuel while cranking the engine?

Sorry Fun times no when i crank it it's 38 and as i let go of the key it spikes to 50 just for a split second

And yes the only way i can make it run is to feed extra fuel down past the injectors

we took the reading from in between the vst and pipe number 16

The serial number is 0F803847

Thanks guys

Well technically even 38 is to high but spiking to 50 is way to high. How trusty was the test gauge and fittings would be a concern.

A clogged or bad fuel regulator would be of concern, so would a clogged return line/system.

 

[650]

Ok i'll check all of above posts and yes i think a video is a good way to show what's happening i'll post one as soon as i can get to the boat

 

[alldodge]

Wonder if what is coming out of the injects is bad gas