250 EFI with 725 hours.

[modvp]

I have a 1999 250 EFI (3.0) with the following run-time:
0k-1k rpm—177hrs
1k-2k rpm—391 hrs
2k-3k rpm—33.5 hrs
3k-4k rpm—37 hrs
4k-5krpm—71 hrs
5k-rpm limit—15.5 hrs
Rpm Limit time—0hrs
ECM run time—725hrs
OverTemp Time—0hrs
Compression numbers range from 100-105 on all cylinders.
The hours are a bit on the high side, is there anything I should be concerned with?

The engine was on a slower fishing boat and now I plan to use it on a high performance rig. Are my compression numbers in range…what are the approximate compression numbers for a vintage 1999 250 EFI?

Thanks!

[EuropeanAM]

Hours are not nearly as important as "how the engine was treated DURING those hours".

90-110 psi, with a maximum variance of 15 psi is the "factory specification" on compression.

Those numbers are WELL within the spec.

Review the maintenance history (so you can have everything up to date, including the water pump). Make sure the gearcase is solid- with fresh lube.

Prop it right... feed it good fuel and oil, and it should give you plenty of good service.

[modvp]

Thank you! Along with the oil-injection, I plan on adding ~1oz of oil/gallon of gas. I've changed the water pump, drive-shaft seal and lower unit gear oil.

[EuropeanAM]

Just be careful on the "additional" oil scenario. I'll admit to having done the same myself with some of my own engines.....

One common myth is that "more oil is better". In reality, there's a point at which the oil/fuel mixture becomes TOO rich (actually too thick), and won't flow properly through orifices, jets and injectors. This results in a LEAN running condition (the very thing someone was trying to avoid).

I wouldn't recommend anything richer than a 40:1 overall ratio for "everyday" use.

[modvp]

Thank your very much for the tip. If my math is correct, then adding 1 oz/gal would make it too rich (~35:1); however, adding 0.5 oz/gal would bring the ratio up to ~40:1.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by modvp &raquo;</TD></TR><TR><TD CLASS="quote">Thank your very much for the tip. If my math is correct, then adding 1 oz/gal would make it too rich (~35:1); however, adding 0.5 oz/gal would bring the ratio up to ~40:1. </TD></TR></TABLE>

That would be about accurate. Doesn't seem like much..... but it can definitely make a difference in the "level" of a failure if the "unthinkable" were to happen.

[Largemouthlou]

If your using this on a faster hull you may want to ck where the limiter hits in on the 250EFI.. Have a rig down this way with one on it and his soft limiter seems to be dumping gas at 5900. With 1.75 gears it is very hard to prop and the motor seems to run out of steam easily..