No power under load

I

Ignatios

Petty Officer 2nd Class
Joined
Mar 15, 2015
Messages
115
Hello All
I have a 350 mag MPI year 2000 on a Larson 330 cabrio, I put in new refurbished block in rebuilt the heads engine starts beautiful not even a full crank and it’s running rubs up good but when I go under power the rpm does not go past 1500-2000 and it doesn’t seems like it’s trying or being restricted but more like it flattens out, I tried the timing no change and it heats up to about 190 or 200 when I adjusted the timing it went down a bit, all sensors seems to be working fine except the IAC when I unplug it no changes in idling, I did compression test all between 135 and 142,
Any ideas? Would injectors cause that.
Thank you very much.
 
achris

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
As it's an MPI you can't adjust the timing. That's all done by the ECU. Set the distributor to the right position (according to the manual) and leave it there. Moving it will not adjust the timing, just run the risk of a crossfire.

To find out what's going on you are going to need the Diacom diagnostic software from Rinda. Without that, you are just guessing.. The engine power is being limited by the ECU, and without the software to tell you why, you can't even has at a guess.

Chris..........
 
Grub54891

Grub54891

Admiral
Joined
Jun 17, 2012
Messages
6,078
I would hope you aren't revving it to high without having it in gear in the water.
 
I

Ignatios

Petty Officer 2nd Class
Joined
Mar 15, 2015
Messages
115
achris said:
As it's an MPI you can't adjust the timing. That's all done by the ECU. Set the distributor to the right position (according to the manual) and leave it there. Moving it will not adjust the timing, just run the risk of a crossfire.

To find out what's going on you are going to need the Diacom diagnostic software from Rinda. Without that, you are just guessing.. The engine power is being limited by the ECU, and without the software to tell you why, you can't even has at a guess.

Chris..........
Click to expand...
Ok sir thank you, so this device is something expensive any thoughts what is the least expensive way to get this test done.
Thanks again
 
Lou C

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,686
In addition don’t forget simple causes of low rpm like a rusted or clogged anti siphon valve or a blocked fuel tank vent.
 
achris

achris

More fish than mountain goat
Joined
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Messages
27,468
Ignatios said:
Ok sir thank you, so this device is something expensive any thoughts what is the least expensive way to get this test done.
Thanks again
Click to expand...
Doesn't matter how expensive it is, it's a tool you require to repair and maintain your engine. If it was a points and carb engine, you'd be buying feeler gauges, dwell meters, vacuum gauges... All the tools to maintain what you have...

The 'less expensive' way is to just buy lots of parts that MIGHT be the problem (or not) and throw them at it. At the end of the day this tool, like most tools, will pay for itself over time.

"Boating is a very cheap hobby", said nobody ever....

Chris.........

BTW, consider yourself fortunate that you don't live somewhere with an inferior exchange rate. The Diacom software is only $600 for you. With the exchange rate, for me it's over $800...
 
Lou C

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,686
You have to make a decision either pay the mechanic for their knowledge of modern systems or make the investment in diagnostic tools and learn yourself. If I had a modern boat for sure I’d have one of those scanners that would pay for itself in a few years. With my old boat I can use the same tools I used to tune up my 1972 Chevrolet!
 
H

havoc_squad

Senior Chief Petty Officer
Joined
Mar 5, 2011
Messages
738
Ignatios said:
Ok sir thank you, so this device is something expensive any thoughts what is the least expensive way to get this test done.
Thanks again
Click to expand...
As mentioned above, I don't have much sympathy when people try to cheap out on what is necessary for boat repair/maintenance.

There's a difference between falling on hard times and trying to skip out on paying what is necessary.

Fuel injection systems are computer controlled and you have to have the diagnostic software/device AND the understanding of the data in conjunction of how the system works before you can actually FIX things.

There is no room for parts cannon work unless you like to be poor spending a lot on unnecessary parts with a boat that doesn't run right.

It's either pay for the tools and service manual, then train yourself how the system works or pay a professional to do the work.
 
alldodge

alldodge

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Messages
42,065
Ya'll hitting a guy pretty hard for asking a question. Being a 2000 it may have the HVS Dizzy with the 555, but depending on the motor it may have a MEFI 1 or 2 and a EST or TB Dizzy.
 
Scott Danforth

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Ignatios said:
Hello All
I have a 350 mag MPI year 2000 on a Larson 330 cabrio, I put in new refurbished block in rebuilt the heads engine starts beautiful not even a full crank and it’s running rubs up good but when I go under power the rpm does not go past 1500-2000 and it doesn’t seems like it’s trying or being restricted but more like it flattens out, I tried the timing no change and it heats up to about 190 or 200 when I adjusted the timing it went down a bit, all sensors seems to be working fine except the IAC when I unplug it no changes in idling, I did compression test all between 135 and 142,
Any ideas? Would injectors cause that.
Thank you very much.
Click to expand...
you have a cooling system issue your engine should not be over 160 if raw water cooled or 180 if heat exchanged cooled

your compression is down on all cylinders, however that could be a few things

you need to get diacom or pay someone whom has it

what is your fuel pressure?
 
nola mike

nola mike

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Joined
Apr 22, 2009
Messages
5,366
havoc_squad said:
As mentioned above, I don't have much sympathy when people try to cheap out on what is necessary for boat repair/maintenance.

There's a difference between falling on hard times and trying to skip out on paying what is necessary.

Fuel injection systems are computer controlled and you have to have the diagnostic software/device AND the understanding of the data in conjunction of how the system works before you can actually FIX things.

There is no room for parts cannon work unless you like to be poor spending a lot on unnecessary parts with a boat that doesn't run right.

It's either pay for the tools and service manual, then train yourself how the system works or pay a professional to do the work.
Click to expand...
Also, keep in mind that whoever is charging you for the diagnostics is screwing you because there isn't any competition. How much is an OBD2 scanner that can diagnose 90+% of codes? Why is that scanner <$75 but the extra 10% of proprietary manufacturer codes will cost $1000's for the factory scan tool?
 
J

j cat

Petty Officer 2nd Class
Joined
Oct 13, 2015
Messages
100
the engines starts great then the fuel is not increasing the to the injectors .
pull the injectors out see if the fuel is spraying good...
well the gasoline is a mess staying in the fuel tank over several months , then the injectors had a flow issue..
 
achris

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
j cat said:
the engines starts great then the fuel is not increasing the to the injectors .
pull the injectors out see if the fuel is spraying good...
well the gasoline is a mess staying in the fuel tank over several months , then the injectors had a flow issue..
Click to expand...
And you know this how?
 
J

j cat

Petty Officer 2nd Class
Joined
Oct 13, 2015
Messages
100
achris said:
And you know this how?
Click to expand...
inspect the fuel injectors .. see if it is goopy..
I have a 350 mag MPI year 2000 on a Larson 330 cabrio, I put in new refurbished block in rebuilt the heads engine starts beautiful not even a full crank and it’s running rubs up good but when I go under power the rpm does not go past 1500-2000 and it doesn’t seems like it’s trying or being restricted but more like it flattens out, I tried the timing no change and it heats up to about 190 or 200 when I adjusted the timing it went down a bit, all sensors seems to be working fine except the IAC when I unplug it no changes in idling, I did compression test all between 135 and 142,
Any ideas? ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, Would injectors cause that.
 
J

j cat

Petty Officer 2nd Class
Joined
Oct 13, 2015
Messages
100
Ignatios said:
Hello All
I have a 350 mag MPI year 2000 on a Larson 330 cabrio, I put in new refurbished block in rebuilt the heads engine starts beautiful not even a full crank and it’s running rubs up good but when I go under power the rpm does not go past 1500-2000 and it doesn’t seems like it’s trying or being restricted but more like it flattens out, I tried the timing no change and it heats up to about 190 or 200 when I adjusted the timing it went down a bit, all sensors seems to be working fine except the IAC when I unplug it no changes in idling, I did compression test all between 135 and 142,
Any ideas? Would injectors cause that.
Thank you very much.
Click to expand...
.... CLEAN THE INJECTORS youtube.com/watch?v=8rk0tKtiVic
 
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