I cannot find the recommended idle speed setting for the 1005 in the manual. It was shipped with the idle set to about 600 rpm. The engine vibrates terribly between 600 and around 950 but runs smoothly beginning at about 1000.
What is the correct idle speed. Will shifting into and out of gear at 1000 rpm damage the transmission ?
If the correct idle speed is 600 - 800 can you provide any advice as to reduce vibration? It is really bad at that speed. The engine runs smoothest at around 3000 rpm.
I should add that the fuel tank is located higher than the Racor 500 filter (Transom day tank) and that there are not fuel starvation problems at any other speed.
Thanks
Mike
-- Edited by mdw on Sunday 1st of August 2010 08:33:16 PM
The idle speed for your engine will be between 900-950 rpm. You can find this listed on the factory engine test certificate that was included with the manual.
With a little bit more information we may be able to help you obtain a smoother engine at idle. Please provide the following.
Model of boat.
Style and brand of isolator mounts that you are using.
Installation angle of the engine.
A photo of the engine beds.
By what method are you reading rpm?
Shifting the marine gear at 950 rpm will not damage the gear.
It sounds like the idle speed needs to be adjusted up just a bit.
Remove the control cable end from the throttle ball connection. Adjust the low idle screw up to around 950 if required to opbain a smoother idle. Then adjust the cable end to sit back down on the ball connection without effecting the idle speed.
Provided you have not changed the alternator, the tach should be pretty accurate. It is a analog read out and not digital so a needle width is worth about 50 rpms.
Well, the best I could do on the idle was 1050 rpm. I did once get it to 1000 but lost it on tightening the lock nut and I could never get back there. There seems to be some slack in the throttle mechanism around this speed so the idle adjusting screw is not a very precise adjustment.
By the way, I did manage to break the slotted end off the idle adjustment screw when trying to turn it with the lock nut a bit too tight. It doesn't take much. Is this a replacement part?
Anyway, I could not get it near 900 - 950 without major vibrations, more tinkering might get it down to 1000 but will I do any damage if I leave it at 1050? I am most concerned about shifting into and out of gear at this speed and the effect on the transmission.
The engine mounting angle is about 7 degrees. I was not able to get pictures of the engine beds but they are solid. The low speed vibration is the engine dancing around on its rubber mounts.
Hello Mike, Dont worry about a special screw for the throttle stop. Replace the original bolt with a standard 6 x 30 mm bolt with 1mm thread pitch. It will work just fine.
I want to confirm the mounts that you are using. Please check that the top side of the mount base has the following number imprinted on it. ( RA60 ) The flex portion of the mount should be round in appearance and not square or rectangular shaped.
Also, please check that all four engine mounts are loaded equally IE: that each mount is doing its share of holding the engine up. It is possible during the alignment process to end up with two or three mounts carrying all the weight of the engine and to have one or two mounts actually pulling the engine down instead of holding the engine up.
This puts the engine in the situation of being balanced on the mounts instead of sitting down solidly on all four mounts. This can cause a severe vibration issue. Particularly at idle.
The easiest way to check this is to completely loosen all four of the top nuts on each mount. Then check the tightness of the bottom nuts to make sure that the engine weight is sitting down equally on the bottom nut of each mount. If any of the bottom nuts are loose or can be easily turned with fingers then the engine is not sitting evenly across the four mounts. You will have to disconnect the prop shaft and realign the engine.
Engine alignment must be obtained with all four top nuts completely loose and all four bottom nuts equally snug to the bottom of the hard mounts on the engine. The only purpose of the top nut is to secure the engine to the mount after proper alignment has been obtained using only the bottom nuts for adjustment.
-- Edited by Farron Peffer on Monday 9th of August 2010 09:36:53 AM
I checked the engine mounts and all is well there. The engine is riding on all four lower nuts.
There is no marking on the engine mounts. Here is a photo of what was supplied by the distributor:
I still cannot get it to idle lower than 1050 without shaking horribly. Above that things are fine. Please let me know if there is anything else I can try.
Mike
edited to add photo.
-- Edited by mdw on Sunday 22nd of August 2010 08:01:07 PM
-- Edited by mdw on Sunday 22nd of August 2010 08:03:52 PM
-- Edited by mdw on Sunday 22nd of August 2010 08:12:48 PM
Great picture. I always like to see photos of installations from the field.
I want to ask you to change out the mounts used on your engine for a set that will be a bit stifffer.
All installations and boats are slightly different and occasionally a particular boat structure and engine combination and setup will require mounts different from the standard.
In this instance I feel strongly that the stiffer mounts will hold the engine a bit more rigidly and solve the shaking at idle.
I will provide the mounts free of charge.
Please call me at 252-249-2473 and we can arrange shipping.
I replaced the motor mounts with the new ones you sent and the engine now idles smoothly right above 900 on the tach (the test certificate idle speed is 905).
Thanks so much for sending me the mounts and diagnosing the problem so accurately.
