Yamaha 90TLRP 1991 questions

[Trout248]

Hello

I just picked up a 90tlrp. Price was right. Some issues though. It did not have a lower unit. The controls were cut 12 inches from the 703 controls. I was told it had low compression on one cylinder. Motor besides that looks new under cowling. Was properly stored and looks used very little.

So my question is where to start?? I can't do a proper compression test. Figure I need to replace the wire harness from control to motor. Put some power to it so I can turn it over?

I have a couple manuals on order. I am going to set it up for a jet so I'mlooking around for a lower.

So my initial question is if I put power to it is it okay to turn it over without a lower?? Are there any other things I can inspect to see if I have a viable motor?

What I'm trying to avoid is putting a ton of money into it without an idea of what I have

Any help would be appreciated

1991 90tlrp. 2 stoke oil injected

 

[triumphrick]

Re: Yamaha 90TLRP 1991 questions

That's such a popular motor, you should have no problems locating a lower unit..if the powerhead proves to be good. I say you're on the right track getting the cable squared away and getting power to the motor. Yes, it can be started quickly without a lower unit, but I wouldn't run it long. The compression test can be done by just turning the motor over ...

 

[99yam40]

Re: Yamaha 90TLRP 1991 questions

low compression on one cylinder means something has gone wrong with that cylinder. Bore scope to see what they all look like or pull the head and or exhaust plate to inspect pistons and cylinder walls.
You can do a compression test easily by grounding the plug wires or the kill wire to keep it from sparking and then jump the start relay to turn it over.

 

[Trout248]

Re: Yamaha 90TLRP 1991 questions

Thanks guys. I'll wait for some manuals and round up a harness. I have the motor on a stand in the house.

I'll most likely have another question or two. Great forum. Tons of info here