To high rpm control. exist? john 175 -92

[Daniel Beckman]

-92 john fastrike 175 v6<br /><br />The engine does not run to hot the temp gauge shows normal temp (dont get any overheat alarm).<br />It drops power exact at 4800 rpm. Im turn it back to idle and it works perfect up to 4800 again.<br />When it have drop the power it kicks up and down with short rpm peaks trying to get power again.<br />Have checked everything with fuel restrict.<br />Do not get any fuel restict alarm.<br /><br />Can any fault high (over rpm) control make this stuf?<br />Is there any over rpm controls of engine like those?

 

[plenox]

Re: To high rpm control. exist? john 175 -92

I had a similar problem except my J175 was losing power at around 2500rpm. The problem was a faulty overheat sensor switch which limits the revs. There is one on each side of the V near the top cylinders. You can check by temporarily disconnecting each one in turn and see how the boat runs. The left one has a single wire and the right one has two.

 

[Daniel Beckman]

Re: To high rpm control. exist? john 175 -92

Thanks Plenox.<br />Will checked them and come back and tell the result.

 

[Daniel Beckman]

Re: To high rpm control. exist? john 175 -92

Checked the sensor and they are ok.<br />Im still figure on how that over rpm control works.<br />I men can a fault in that "unit" maybe think that the engine is getting to high rpm and therfor put it in SLOW mode?<br />Anyone?

 

[plenox]

Re: To high rpm control. exist? john 175 -92

Yes. The sensor is just a switch to earth. If it corrodes inside it will short to earth and activate the engine speed limiter. But if you have disconnected them and the boat still does not rev freely it must be something else - timing, fuel starvation etc?

 

[Daniel Beckman]

Re: To high rpm control. exist? john 175 -92

OK, but i dont think its a fault in the heat sensor (did check them)<br />Nothing with fuel restrict cheked all that two.<br />But the engin hits SLOW at the exact same rpm all the time (4800) thats why i thinking of an fault in an over rpm control (or whats it called).

 

[G DANE]

Re: To high rpm control. exist? john 175 -92

Hi Daniel<br /><br />If your motor has an overrev protection, it is integrated in the powerpack. One of the members on this board who is an electronic ingeneer drew a circuit schematic showing how this works. I will email it to you. I think it just reacts based on a given current. And of coarse, this could be faulty too. I am beginning to think you are on the right track. The S.L.O.W mode would take it all the way down to 2500 RPM which is not what you experience. I am not the right guy to tell you wheather your motor has this feature or not, my manual does not contain this information, but i think a dealer can look it up from the type number at pack.

 

[Daniel Beckman]

Re: To high rpm control. exist? john 175 -92

Thanks G DANE.<br /><br />I have order a service manual but not got it yet.<br />Well, i think the engine going down to 2500 rpm when it hits 4800, but i cant be sure cause it start to kick up and down with short rpm peaks trying to get power again, so its hard to see exact what rpm i do get when it fall down. <br />But i really feel that it lose lots of power.<br />Last summer the SLOW kicked in when i was going backwards for a little to long time (on the way to overheat i guess, didnt get enough water cause i got a nose cone that pics up the water)<br />And if i remeber right the power in the engine pretty much felt like it do now when it lose the power.

 

[OBJ]

Re: To high rpm control. exist? john 175 -92

Daniel...your engine's SLOW system is kicking in causing the problem you've described. Ususally, the power pack is at fault when this happens. You can do a couple tests which will be in the manual, if your getting the OEM manual. One, with the engine running, individually ground the tan temp sensor leads and see if the engine slows to 2500rpm. This will verify that the sensors are ok. Two....find the six pin connector between the stator and power pack and separate. Measure the resistance between "E" and "F" pins from the stator. Should read 96ohms +/- 10ohms. You can also read to ground from each pin. Should show infinity. If all this is good, most likely the power pack is at fault.<br /><br />Keep us posted...thanks.

 

[Daniel Beckman]

Re: To high rpm control. exist? john 175 -92

Thanks again.<br /><br />Will keep you update what i get.