86 V6 150 Evinrude Warning Siren

[Oshi]

This motor is on an 86 model Ranger 371V. 24 pitch on a reconditioned prop. My question is this: When the boat is run around 4900 RPM and you back off the throttle and trim the motor back down the warning siren will come on. It does not do it all the time, just when you come off of plane and you go to trim the motor back up to trailer, etc.. In other words, while fishing on Thursday last week we ran it for about 20 minutes at 5000 rpm and went to load the boat, and when I trimmed the motor up, the siren came on. We took off again and trimmed it out while running and it ran fine, no problems with acceleration or deceleration. It just seems to do it when you idle around with the motor trimmed up. I know that you cannot idle those motors for long periods of time, so it was not intentional if it got hot. Is it possible that I am trimming to high, I watch to make sure the intake is still in the water, and the Oil injection has been taken off so you have to mix it by hand. Is it possible that the engine could be running hot? The man selling me the boat said he would change the water impeller, and thermostats for me at no charge. He really wants me to be happy with the boat and this makes me feel a little better. I just would like to know what could be causing this. When the motor is trimmed up would it be safe to keep the rpm's down to keep this from happening? Sorry for so many questions, I am just needing some input from people who know. <br />Thanks for your help<br />oshi

 

[rickdb1boat]

Re: 86 V6 150 Evinrude Warning Siren

Oshi <br />I would wait until he changes the Water Pump and the T-Stats. Then try it again. It could be overheating at low speeds due to a worn impeller, but it would tend to overheat at higher speeds if it was the thermostat being bad(Stuck Closed). Are you sure the lower unit was far enough down for the water intakes to pull water?

 

[Oshi]

Re: 86 V6 150 Evinrude Warning Siren

I thank you for your comments. I believe you are right. At high speed the thermostats seem to be working. If the impeller checks out and is changed and it happens again, what else could it be? I forgot to mention that it was high pitch long siren not the short beeps. If this helps any. Thanks for your help.<br /><br />I meant to mention about the compression also: <br />1 100<br />2 105<br />3 100<br />4 100<br />5 96<br />6 98<br /><br />Are these okay? Some say too low and others say too high. These are numbers on a cold engine and it had not warmed up.<br />Thanks for help<br />oshi

 

[rickdb1boat]

Re: 86 V6 150 Evinrude Warning Siren

The long substained warning horn is the overheat alarm. The compression reading are OK, as they are close to being within 10% of each other and that's a cold reading. Change the pump and see how it goes. Be sure not to raise the lower unit too high when running slow and you should be fine.

 

[Oshi]

Re: 86 V6 150 Evinrude Warning Siren

Thank you so much for your help. I appreciate what you are willing to share with others. I will let you know what happens. Tuesday is the day the deal may be finalized. Thank you again for your help!<br />oshi

 

[rickdb1boat]

Re: 86 V6 150 Evinrude Warning Siren

Oshi <br />After re-reading your post, it seems as though this alarm is happening at a certain tilt or trim level. You might want to check the wiring and check for a short to ground from the temp. sensor wire(Tan Wire). If you have the opportunity, try running the lower unit up and down with the boat on the trailer with the key in the ON position and see if this triggers the alarm. Also, as for the compression readings, as I said, they are OK.<br />But it would be better if they were higher(125-135), as 100PSI is a minimun you would look for. Have them do a warm reading and see if they come up. It may just need a decarb to bring it back up. Just some more thoughts, since you are buying this boat, I just want to make sure you have covered all the bases!

 

[Oshi]

Re: 86 V6 150 Evinrude Warning Siren

I agree with the compression readings. I think if they were hot, then they would come up some. I will have to try that and see if it works. The compressions were taken while the motor had been sitting for around a month, so that could be a reason also. In my opinion, I am trimming the motor a little to high after running it on plane. I will have to be carful for that. I have tried to run the trim all the way up and down with the key in and the alarm did not trigger. I will keep you informed. Is it possible that the motor could be worn out with the low readings? Is this a good indicator that the motor might blow? Sorry for the questions and I know that their are no guarantees on anything used! Thanks for your help!<br />oshi

 

[rickdb1boat]

Re: 86 V6 150 Evinrude Warning Siren

Oshi <br />Like I said, the readings are boarderline. But if it has sat for a while and it was tested cold, it may be giving false readings. Or it could be carboned up. Still, check the reading when warm after a run and see what they are then. As I said, 100PSI is a minimum, but more importantly is that they are fairly even reading(+-10%). It sounds like it runs strong from what you have said, so I don't think I would be too concerned at this point. Odds are since it sat for a month, the oil has drained from the rings and they are not providing maximun sealing for proper compression readings.

 

[Oshi]

Re: 86 V6 150 Evinrude Warning Siren

I talked with an Evinrude mechanic today and mentioned what you said about the tilt angle and he stated what you stated before. The impeller is probably worn and needs replacing which would cause it not to cool properly at low idle speeds. I also mentioned the compression readings and he told me that was fine. He wanted me to bring it in and we would run it and take the compression test again and see what it says. I hope that this solves the problem. It makes sense to me that the motor could not be cooling properly at low speeds, but be cooling fine at high speeds. There is a lot more water coming through at 4800 rpm than 1000 rpm! I have one more question: I am running a reconditioned 24 pitch prop, and at full tilt according to the gauge and just me in the boat I can get 52 mph at 5200 rpm. Is this too high? What is the max rpm I should run? I do not want to overrev the engine. I consider 4200 to 4800 rpm a good cruising range, or at least as fast as I would like to go! Thanks for your help<br />oshi