Which propane conversion kit did you use?
I used the Nash Fuels kit. Would I go with them again? Probably not, since their documentation is totally generic and was not developed for each specific generator kit that they offer.
Also, their "load block" variable orifice for adjusting the mixture is a totally crude hack, a steel bolt threaded into a brass NPT tee. It results in a way too coarse adjustment range that is consequentially really hard to tune. Their documentation on how to tune the mixture is also almost useless. Much better to replace their "load block" with a 1/2" NPT needle valve so that you can actually adjust the mixture precisely.
However, I went with the Nash Fuel's "tri-fuel kit" because they also sold all the other stuff I needed to safely automate my remote installation (12 V propane shutoff solenoid valves, solenoid electrically primed Garretson regulators, vacuum safety switches to shut off propane solenoid valve in event of uncommanded engine stop etc.). You would probably be better off to get a kit elsewhere and just order these specialty items from Nash Fuels, although their shipping department was really slow in getting my kit out the door (making me think that they don't actually have those additional bits in stock).
On the plus side, Nash Fuels have kits available for most generators. They have a range of kits for each, for some generators there is a choice of kits with nice billet machined Al propane venturis or 3d plastic printed propane venturis. I went with the 5/8" thick plastic one because it is thinner than their Al one and most of the H3000's have no room for the larger venturi. The plastic one will probably last forever anyways given there is little stress on the material.
Once you figure it out, installation could be pretty simple despite their absolutely useless instructions / documentation. As result of the confusingly vague instructions and illegible and irrelevant drawings, I made several assembly mistakes (initially put the venturi inside the carb and screwed up the choke by unnecessarily removing the carb, mixing up the carb washers as well as a result - the metal washer goes only on one side of the carb or the choke mechanism won't work properly since the washers are different thickness). They give you extension nuts that work pretty well to extend the carb studs by the needed 5/8".
All you really need to do is take the air cleaner off, put venturi on carb (using extended nuts) and replace air cleaner (using spacer and extended 6mm bolt - which wasn't the right length in the kit so I had to buy another one of the right length).
Generator runs pretty well on either gas or propane now, but it took me a while to get all the bugs worked out.
For best starting on propane, switch the stock plug to the equivalent NGK Iridium model (the iridium plugs identifiers end with IEX) or better yet, the NGK Rhodium model and reduce the gap by about 10% (I am running mine on 0.022" instead of 0.026") since propane is harder to ignite (but burns hotter so you can go to a one step cooler plug than stock).
