ran out of oil and engine does not go as fast and the rpms are lower

[86bayyliner]

my friend ran my boat out of oil and got towed in and i went and got it running the next morning sounded good. then i took it out on the water and wot doesn't rev out as much and its alot slower. does anyone know what could have happened.. its running fine?? 1990 evinrude 150 2 stroke..

 

[iwombat]

Re: ran out of oil and engine does not go as fast and the rpms are lower

I think you need a new friend.

Time for a compression check.

 

[kenmyfam]

Re: ran out of oil and engine does not go as fast and the rpms are lower

Agree with iwombat, choose your friends more carefully !!!!
Do the basic health checks and go from there but you could be looking at fried stuff (pistons, rings, cylinder walls, heads etc) and even main bearing damage.

 

[kenmyfam]

Re: ran out of oil and engine does not go as fast and the rpms are lower

By the way, No warning horns ??

 

[cougar1985]

Re: ran out of oil and engine does not go as fast and the rpms are lower

lets not automatically blame the friend !i know from my own perspective i always make sure my yamaha oil injected snowmobile is always topped off after every ride.that gives me a 3 tank cushion in case of any problems like not being able to find syn 2 stroke oil when using.always make sure if your lending a machine out that the operator knows the basics such as where to put oil etc and maybe this wouldnt of happened.if this motor ran out of oil after a day trip i place the blame on the owner for not making sure it was full to begin with.

 

[86bayyliner]

Re: ran out of oil and engine does not go as fast and the rpms are lower

well the friend is part owner but has not really pulled his weight with working on the boat.. he used it last and doesn't do the checks like i do before i take it out.. im always washing it down and working on it whenever something goes wrong and to top it off we cant even do wiring together because he is color blind..lol.. so im going to do compression tests ,, they should be in the 90s right?? if thats all good what should i look at next? so far i rewired the dash so that it all works because its an 86 bayliner and im not the first person to tamper with it.. i changed the water pump changed the lower halfs oil.. went through the carburetors {before the problem} and they were fine..do you think i could have a clogged jet or something?

 

[wilde1j]

Re: ran out of oil and engine does not go as fast and the rpms are lower

What's the compression??? The most likely issue is mechanical damage due to lack of oil.

 

[caver95]

Re: ran out of oil and engine does not go as fast and the rpms are lower

Is he going to pay for the parts?

 

[86bayyliner]

Re: ran out of oil and engine does not go as fast and the rpms are lower

but it starts up and runs fine.. the only thing its not the same at WOT

 

[gene8084]

Re: ran out of oil and engine does not go as fast and the rpms are lower

Starting is basic. Enough compression to start doesn't ensure you'll have enough power under load. Ever try to ride a moped up hill without peddling?

Lack of compression = lack of power. Fried rings allow blow by and could explain reduced RPM's.

So, as many have suggested here check the compression. Warm it up first.​

 

[86bayyliner]

Re: ran out of oil and engine does not go as fast and the rpms are lower

Of it is bad rings how hard is it go fix that. My father owns a transmission shop so I have an unlimited amout of tools.

 

[gene8084]

Re: ran out of oil and engine does not go as fast and the rpms are lower

It's not trivial, but doable with the right shop manual.

First you need to know what's wrong. Hopefully he has a compression test kit (~$60.) amongst all those tools.​

 

[wilde1j]

Re: ran out of oil and engine does not go as fast and the rpms are lower

If the compression is down and you open it up, you may find a bunch of damage (rings, bore, bearings, conrods, wrist pins, crankshaft, etc.) It may not be economic to repair ... a replacement rebuilt may be way better path.

 

[86bayyliner]

Re: ran out of oil and engine does not go as fast and the rpms are lower

well thats what it was.. i took the spark plugs out and found that there was a deteonation and closed the prork plug gap up and when i took off the head the piston was charred up and the rings came apart.. now that thats known the cylinder head is not messed up im going to hone it a little but what is the easiest way to take out the piston..>??????

 

[iwombat]

Re: ran out of oil and engine does not go as fast and the rpms are lower

Total powerhead removal and rebuild is what you're looking at. No short cuts.

 

[wilde1j]

Re: ran out of oil and engine does not go as fast and the rpms are lower

If you think you're going to mess with it, get an OEM shop manual (not Clymer's, Seloc, etc.). Sounds like you're looking at a lot of parts. Check the parts out at BRP's website. If the gaps were closed, a good chance your looking at most likely all or most of what I outlined above. When you see the cost, you may quickly decide against rebuilding your block and getting one already done. Check here at iboats for rebuilt powerheads. BTW, I don't think OMC built a 250 in 1990. Is it a 225? If so, plan on ~ $3500 for a rebuilt.

BTW, you're looking at ~ $3800 in parts alone w/o any soft part parts if the damage is as bad as probable. You could probaly save some using third party parts, but not enough to mess with.

 

[86bayyliner]

Re: ran out of oil and engine does not go as fast and the rpms are lower

but what do i have to take off to remove the piston.. i already have a new piston,rings and gasket.. what does it intail???

 

[iwombat]

Re: ran out of oil and engine does not go as fast and the rpms are lower

You need to remove the powerhead, split the cases, get the cylinder bored a size or two up, and install new piston, rings, gaskets, etc. Speaking of which, how did you know what oversize piston to buy if you haven't taken the cases apart and had the cylinders measured up?

 

[wilde1j]

Re: ran out of oil and engine does not go as fast and the rpms are lower

Try an OEM shop manual ... to much to possibly cover here. You do know the cylinder will have to be bored oversize and the piston and rings must match the oversize boring? The powerhead has to come off, e strpped down, the halves separated, and all parts removed to remove the piston and replace. That's just the broad strokes ... much more detail to it.

Wow, i you're fast!

 

[kenmyfam]

Re: ran out of oil and engine does not go as fast and the rpms are lower

but what do i have to take off to remove the piston.. i already have a new piston,rings and gasket.. what does it intail???

As said the powerhead MUST come off. Is it just 1 piston showing the detonation ??? My guess would be that the others need some attention as well.