my dads 89 xr4 was nerve racking to start,he would run batt down alot of times.you may try what works on his.
back it in so that the caviation plate is just under water,i pump the key 4 or 5 times,hold the key in while cranking with just a little fast idle engaged,it will fire up very quick this way.
his vision fish n ski sets very low,if you back it all way in the exhaust is so far under it hampers starting.