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Blind Hole Mounting Bolt Size and Thread
Whalestales01966	#1  Posted on 04/27/13 - 8:43 AM
Member Posts: 7 Comments: 0 Joined: 08/12/12	Anyone know the exact size and thread of bolt used on the "blind holes" of a 1990 Yamaha 90ETLD? Yamaha dealers say they have never heard of it. The diagrams on Yamaha.com show the hole but not the bolt. I have seen the discussions on filling and re drilling v. jackplate. I guess I'll do that if there is no other choice. Holes are there. Engine is a nearly exact replacement of the Yamaha 70 it had. Just need the bolt / thread size if it exists. Just want to get her in the water this summer and see how it goes. Maybe deal with raising it up and drilling new holes in the fall. Thanks.
Tom W Clark	#2  Posted on 04/27/13 - 9:23 AM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	A 1990 Yamaha 90ETLD id not use any blind holes, it uses an auxiliary bolt holes location that matches the blind hole location. This location was first used in 1960 by OMC and was an auxiliary hole location, but it was not a blind hole.
Whalestales01966	#3  Posted on 04/27/13 - 9:38 AM
Member Posts: 7 Comments: 0 Joined: 08/12/12	Thank you very much for the reply. The holes I see don't go all the way through and they are threaded. They also line up with the holes on the transom which are not for the now standard pattern. Any idea what bolt would thread into these holes to secure the engine to the transom? I do have a picture but not sure how to attach it.
Tom W Clark	#4  Posted on 04/27/13 - 10:53 AM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	Well, the you do have blind holes (holes that are threaded but not drilled all the way though the casting of the mounting brackets.) I opened the exploded parts diagram for a 1990 Yamaha 90ETLD and they do not show the bracket as using blind holes. Yamaha probably used a 12mm x 1.75mm.
dgoodhue	#5  Posted on 04/27/13 - 7:32 PM
Member Posts: 278 Comments: 0 Joined: 10/04/05	Mounting the engine with the blind holes is going to be the wrong engine height. I would just fix the holes and mount it correctly the first time. Dave
Tom W Clark	#6  Posted on 04/27/13 - 7:52 PM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	I agree. You do not need to worry about what thread size you need for the blind holes if you fill the lower holes and drill two new ones on the BIA layout. Why go to all the trouble of mounting the motor twice when you can do it right the first time and be done with it?
Whalestales01966	#7  Posted on 05/05/13 - 7:20 AM
Member Posts: 7 Comments: 0 Joined: 08/12/12	Advice much appreciated. Plugged the old holes. Drilled new. No problem. Mounted the engine. Next I'll try installing steering and throttle.