Boat bogs down at full throttle and max at 3,500 rpms

[Jhilton0816]

i have a 2001 Larson 234 escape deck boat We recently replaced my 5.7l Volvo gsi pefs 280 hp with a 5.7l from marine power310 hp...due to the old engine having cracked heads It was just the block and the top end. All the accessories and throttle body got swapped over.
He problem I'm having is is that I can't shoot out of the hole or it will bog down, or if I go full throttle it will bog Down.
I also can't seem to go past about 3400 rpms. And when I have 7 people on he boat it takes foreverrrrrr to speed up to plane out. I just want to get this boat running right, please help

 

[Scott Danforth]

what is your fuel pressure? have you cleaned the screens in the fuel cell?

 

[Jhilton0816]

I don't know either of those. And I don't know how to do them either, I know the Injectors look somewhat dirty

 

[Jhilton0816]

The screens looked fine from what I saw but I just took the assymbly apart and sprayed it with carb cleaner anyway. But now I have to find one of the small o rings since one snapped as well as one of the bigg orings because it snapped to before I can put it back together. I'm also going to put a new filter on, I was wondering if you think Oreilly's or auto zone would have a filter that would work?

 

[Jhilton0816]

Can anyone please help me find the the small orings for the pumps.... I went to Oreilly's but the closest one they have is to fat

 

[dypcdiver]

Some time in the past someone listed all the "O" ring sizes, perhaps try using the search button.

 

[Jhilton0816]

Screens weren't that dirty I cleaned hem anyway,the fuel filter looked all brown and rusty on the inside, so I got a new one on there now... Now I want to look for the fuel pressure regulator but I can't find it. It's a 5.7l volvo penta gsi pefs 2000 year. I want to clean the screen on the regulator before I test the engine on water but I can't find it, can someone help

 

[gbeltran]

The regulator is on the back of the throttle body. I would get a fuel pressure test gauge and test the pump output before I took the regulator apart. It's not like the multi port version where it easily pops off the rail. Little more involved in the disassembly.

 

[Jhilton0816]

Ok so I went to Oreilly's and bought a fuel pressure gauge and I'm not sure if I hooked it up right but here's a video of me doing it with my boat on ear muffs.... https://m.youtube.com/watch?v=c9fWZZSKpjA
If I did it right then I'm guessing that fuel pressure is low? Idk what to do from here, I've already replaced fuel filter and water separator haven't gone to the lake yet to test that out.

 

[Tail_Gunner]

Your testing the low pressure side, on the back of the tbi that is where you test the pressure and it should be 28/31 lbs.

 

[Jhilton0816]

Here's the photos of my tbi, I can't seem to find the connection for the gauge, as well I don't see the fuel regulator anywhere that was mentioned earlier

 

[Jhilton0816]

http://s614.photobucket.com/user/jeremy_hilton2/slideshow/

 

[Tail_Gunner]

There's the port....See the brass coupler on the alum fuel rail right there.

 

[Jhilton0816]

cool i appreciate it . ok well at idle on muffs it sat at 30 psi constant, i then grabbed needle nose pliers and pinched the return line and it jumped to 60 psi...... does that indicate a bad pressure regulator or is that normal?

 

[Tail_Gunner]

cool i appreciate it . ok well at idle on muffs it sat at 30 psi constant, i then grabbed needle nose pliers and pinched the return line and it jumped to 60 psi...... does that indicate a bad pressure regulator or is that normal?

All things are normal so far. But you need to see if the pressure is constant at 3000 rpm...short burst now there is no load on the engine say 30 seconds or so.

Take a neon light and illuminate your injector spray pattern do a vid and keep the surrounding light level low so the neon illuminates the spary well.

How was this engine timed there is a special process that must be done.

 

[Jhilton0816]

so run the engine up to 3000 rpm in water in gear or 3000 rpm on neutral on muffs or 3000 rpm in gear with prop spinning on muffs? and the mechanic that installed the crate motor said its timed at 29 at 4000 rpm.

 

[Tail_Gunner]

No the first thing you do is to see if its timed correctly 29 AT 4000 is meaning less but sounds right. Im in a rush now so google Timing a penta mefi 3 is very simple If the timing is right then proceed with the other.

Bonk there ya go


https://www.google.com/search?q=Timi...ums.iboats.com

 

[Tail_Gunner]

That shoul




d get it

 

[Tail_Gunner]

Hmm having trouble posting this on to one post so below is how you short the ecm out to base timing mode. Always warm the engine prior to setting the timing. IT should be set at 8 degree's at 1100 rpm

 

[Jhilton0816]

well ihavent done anything since last time to the boat, however today i decided to jump out and check the fuel pressure again because i was bored.... this time the i let the fuel pump primp like normal and its obviously does this steady whine noise like it has done since we got the new motor installed in the boat. well i start it and the pressure is staying at like below 10 psi like 5 on the pressure gauge...... mind you i havent messed with it, so its hooked up still to the tbi in the back.
i turn it off and bleed the pressure gauge. and i let the pump prime again.... well this time there is no beep to let me know its priming and i start it and it almost sounded/ looked like it misfired but started. and once again pressure just is barely there.....i reved the engine and to no avail pressure did do much.... so im coming to believe in my own opinion its just that the fuel pump is bad.... for all i know its the same fuel pump thats been on there for 14 years, its a shame though because when i took the pump apart that so called paint was intact not a scratch or peel on it..... it looked fine.....i might end up just buying a new fuel pump and regulator and hope that fixes it. of course depending on what yall think