Topic: V4 Evinrude/johnson 90 hp outboard

[Hush]

My boat has sat for 5 months on it's trailer and I was going to attempt to remove it from the trailer tomorrow by tipping it into the tide.
I ran the motor this afternoon in the driveway using the "muffs" and as the motor warmed up the low oil alarm started screaming.
This has happened before to me with this motor, once when it actually got low and once when I mistakenly put the tank backto front and once on the plane the oil all ran to the back of the tank making it think it was low.
This time though the tank is flat, the oil is full.
If you have one of these engines can you tell me, the alarm is only a signal from the oil tank right?
The motor does not have any alarms I believe, motor is a 1993 vintage with 110 hours since new.

[Frankencake]

To answer your question with a question:  This is an oil injected two stroke that we are talking about?  If it is, then there is no oil sump.  I don't think that there is a sensor on the lower unit but that is something you should check anyway.  Pop one of the screws out of the lower and see if you have a good color of gear oil in there. 
IMO, there is no other warning system other than the oil tank sender.  Keep it full and you won't have any problem.

[Magpie]

I have an older V4 Evinrude 90 that I have to mix the oil and gas. There are overheating sensors on each head and a warning alarm/horn in the throttle/gear change unit that will go off when it thinks the motor is too hot. I have a friend with an oil injection OMC unit that had a warning alarm that would come on if there was a low vacuum in the system. He checked the level in his oil tank but forgot to pump it up with the squeeze ball in the oil line. The alarm went off, he turned white as a sheet and we had to figure out the problem in the middle of the Broken Island Group in Barkely Sound. Exciting!!
Cliff.

[333]

I'm not sure what the lower unit has to do with an oil injector.  Certainly the oil doesn't go through there.  And there are no alarms in the gearcase.  If you get the exact model number and go here;

http://www.marineengine.com/parts/parts.php

This might give you some diagrams to help figure out what's going on.

[Frankencake]

I'm not sure what the lower unit has to do with an oil injector.  Certainly the oil doesn't go through there.  And there are no alarms in the gearcase.  If you get the exact model number and go here;

http://www.marineengine.com/parts/parts.php

This might give you some diagrams to help figure out what's going on.

The lower doesn't have anything to do with the injection system.  I was just mentioning another maintenance point.  The temperature senders are a good point.  Make sure that the alarm is not tied to those senders. 
Is the water circulating through the motor properly?  Is your impeller junk?  What is the temp of the water as it is exiting the motor after warm up?  Is your oil level up?  Are you running the motor on the hose and is the hose collapsing from too much vacuum?  (I've seen it)
I know that Mercury engines have an alarm for temp and oil.  They use the same noisemaker for both so you don't really know which is happening.  Do you have a gauge for temperature or an idiot light?
Is the boat afloat?  Have you thrown the proper amount of money in the water prior to starting the motor? That, right there, could be the problem.  

[333]

What is the proper amount of money to be thrown in the water?  Does it matter if the boat is fiberglass or wood?  I've heard that it does, but I don't believe it.

[Frankencake]

What is the proper amount of money to be thrown in the water?  Does it matter if the boat is fiberglass or wood?  I've heard that it does, but I don't believe it.

The fiberglass to wood ratio is a well discussed topic.  Pretty much, as a rule:
Fiberglass:   way too much $$$$. probably more than you want to.
Wood:  All of your $$$$, time and patience resulting in a slowly rotting and sinking boat.  Wood boat are perpetually under attack from things that eat them on a microscopic level.  Just try to stop it.... Boo ha ha ha ha

[Spanner 1]

I was always too scared to start my o/b motor out of the water with 'ear muffs' after I saw what an impeller looks like within 30 secs. of running dry !!! It's all over the Mercury repair book not to run above idle and only for 1 or 2 mins. at a time on a garden hose.....

[Hush]

All good guys and thanks for the suggestions and replies, we took "ROKA" out for a run today, all went well until we got into the channel then off went the oil alarm again, we were about to return to the jetty when it stopped.
Being an optimist I said lets just go for a quiet cruise and if we need a tow home we can call a mate who was fishing further out.
Anyhow the engine behaved well, I think now that as I had the oil tank (separate unit altogether) and it's sender etc out for a clean up in petrol, there may have been a small air bubble in the line.
It seems that the low oil alarm is just part of this separate oil tank, we don't have the luxury of heat alarms and the impellors were replaced last year when the frozen open thermostats were changed.
Bad points of the day, no fish and the wind changed blowing a filthy Nor-easter at us to battle home against, but boat works and we had a day on the water.