rob vanharten

Have some 598's with 10-71 blowers, boat is new to me and the motors surge from about 700 to 1400 rpm's. After the motors are warm they die when put into gear which makes docking and loading very difficult. Anyways I was playing with the idle mixture on my Holley 750's trying to prevent them from dying when going into gear, and now when I try to get on plane the port motor kicks and bucks, stumbles and dies. If I turn out the idle mixture screws past 2 1/2 turns it will get on plane with less hesitation and stumbling but then idles terribly and loads up as well. Played with them for 5 hours this afternoon on the water adjusting 4 corner screws and could not get them right. Starboard motor is great surges but doesn't die in gear and is smooth as silk getting on plane. Port motor will free rev great, but as soon as you put a load on it, it bucks, stumbles, chugs, and pops. It has twin Holley 750's on each motor, and the port motor is also leaking fuel between the v adapter and the blower. Could it be sucking air when in vacuum and causing it to go lean? Carbs look old and crusty and I am sure could use a rebuild and tune. Anyone in/near MI that rocks with these holleys? Don't want to be down to long while these get rebuilt.

rob vanharten

Also starboard motor fires as soon as you hit they key, instant nice and stong. Port motor turns over for a good 10 seconds and then slowly catches and builds rpm's gradually. I feel it's lean?

MILD THUNDER

iTrader: (3)

You definitely don't want any vacuum leaks below the carb. I'd start by blowing out the air bleeds with carb clean, using the straw attachment. 750's are a bit small for a 598 with 10-71's IMO. But that's not whats causing your issues.

rob vanharten

I was hoping you would weigh on this Mild. Pulled the the carbs and the v adapter off this morning. When I opened up the primary's slowly on the front carb only one side would spray, other side just dribbled out. If I snapped it open fast it would spray from both sides but still a weak stream compared to the other side. Think I found my lean issue! I really don't know anything about carbs I was told they were 750's but how would I tell for sure? I want to have both of them cleaned and rebuilt, and then re seal the v adapter to the blower. The adapter gasket looked good, would you recommend a gasket and some sort of goo to help seal it? And who can rebuild these?

Rookie

iTrader: (4)

Get the #'s off the carbs and cross reference them.They are pretty simple and straight forward to rebuild.
http://www.mopar1.us/carbs.html
http://www.youtube.com/watch?v=HtsfgxnyN6o

ThisIsLivin

How's your timing? I was having similar problems that were solved by locking the distributor, starts and idles like a dream now.

rob vanharten

Timing was set and locked, and I checked the distributor. Still tight has not moved. I think I have it figured out, but will know for sure when the carbs come back.

ThisIsLivin

When I say locked, I mean that the mechanical advance is locked out so the timing is fixed at 34 degrees. This gives you more timing at idle for a smoother idle.

rob vanharten

Sorry, yes timing is locked at 32 degrees. I sent all four carbs out for a good cleaning and rebuild. Also turns out they are 850's, throttle bore measures 1 3/4.