717 Rotary Valve Cover

[tvpierce]

I have a ‘99 GTS with a 717 single carb. I’ve done a bunch of work on it: cleaned carbs, replaced entire fuel system, replaced head gasket. Here’s my problem: it starts fine on the trailer, but when I put it in the water it won’t start. From what I’ve read, that’s a classic rotary valve clearance too large.
I’ve read that even if I get a new one from SBT, there’s no guarantee that it will bring it back to spec. Is that correct?
What’s the best option?

 

[mikidymac]

First things to do is check compression and rotary valve clearance. Are they within spec?

 

[tvpierce]

Hi Mikidymac.
I’m at the lake now. Having a family member bring the compression tester and feeler gauges when they come.

Thanks.

 

[mikidymac]

Hard starting on the water is typically low compression, fuel issue and lastly rotary clearance.

Unless there are gouges on the cases a refurbished cover can typically fix the clearance but measure it first as some have gotten back covers that are worse.

 

[tvpierce]

Quick question about checking RV clearance: I see a lot written about the solder test. Is that preferred or are feeler gauges sufficient?

 

[mikidymac]

I have always used the solder method but both should work.

 

[burtshaver2021]

Don’t forget to take the intake manifold off to remove the oring before measuring