I am completely new to mud motors, but a buddy is letting me use his homemade longtail rig this season since he is no longer using it. It's a 16 hp vanguard on a 1436. I sent it to a local small engine shop and had him go through the motor before we took it out. It runs great out of the water, but is a dog once put under a load. With one 180 lb person and a small tool bag it would only get up to 6 mph. I asked my buddy and he said it should be going way faster than that. There is no tac on it so I have no clue what the RPMs are. Also not 100% on prop size either, but it does look a little beat up. Any suggestions so I don't have an hour ride to the blind in the mornings?

I'm no LT expert but there's a few on here that will help you. Does the engine bog or does it just not go fast? You should measure the prop from tip to tip.

It bogs down.

Bet there was some old gas in there that turned to varnish. How long was the motor siting till you got it?

If you take the prop nut off there should be a size stamped into the hub of the prop. Should be 9X3. A larger prop would bog engine because engine just isn't strong enough.. also measure widest point across prop. Left to right. If its over 9 inches. Wrong prop. Hope this helps.

Clean the carb, too

Thanks for all the replies. I also forgot to put in the original post that when I disconnect the left spark plug wire, the motor still runs basically the same. If I disconnect the right, the motor kills. It also idles fairly rough and has the same amount of power at half throttle that it does wide open when it is under a load.

Trousertrout, the engine sat up for close to 3 years. Before he parked it, he "claims" he drained the motor of all fuel and ran seafoam through it. I did buy a brand new tank, hose, bulb, and connections for it and ran it with that. I also changed the inline fuel filter, oil, oil filter, spark plugs, and air filter.

Kibb, supposedly the repair shop I dropped it off to cleaned out the carb. I'm not sure if they re-kit it or not. Hopefully it doesn't need a new carb, because the price I got from Congress Outdoors in Lafayette bout floored me!

Coupe, thanks for the info on the prop. When I get back in town I'll check it out.

Ah ha. Hate to say it but you should pull the valve cover on the cylinder that doesn't change when you pull the plug wire. I've had 3 different welders that had vanguard engines. Check the rocker arm nut. The nut has no loctite or pinch nut. The nut vibrates loose and allows push rods to come out of rocker arms. It your lucky its loose and rods are just sitting there. If your not lucky the push rod is either bent into a pretzel or broken and fallen down push rid hole in head and down into crank case. (Would have to split case and remove) to keep rod from damage the crank or crack the case. Hope its just loose and laying there. Thus would explain why UT runs ok when out if water but falls on its face under load. My welders ran ok untul you put under a load. Hope this helps.

Have you cracked into the block yet there has to be a reason that push rod would come out of place? I would check out the cam and the block and make sure there is nothing loose floating around in there. Also check the valve lash because your rocker could be bent or have come loose. Just some ideas.


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