OX66 running ruff

[storm 22]

ruff idle and hesitation on start of run runs great on plane all the way to 6k changed plugs and no change what do ya think

[21XDC]

TPS adjustment....

[storm 22]

how do you ajust it

[craigs06]

From the rear looking forward, on the right side of the engine, disconnect the top butterflies for the throttle bodies. On the left side, disconnect the oil pump rod. The throttle position sensor is on the left side of the engine next to the top throttle body. Find the 3 wire plug down near the VST tank. Push the probes of a DC volt meter into the plug with the pink and orange wires, don't unplug the connector, push the propes in along side the wires. Loosen the 2 phillips screws on the TPS and move very small amounts until you have between .48 and .52 volts. Tighten the screws, repeat until you are between .48/.52 volts, when you tighten the screws, the TPS stresses enough to move the reading. It VERY sensitive. You will learn to set the reading a little out of spec to compensate for the tightening. Reconnect rods, go boating. I have the procedure from the manual, I'll find and e-mail to you. The steps in the manual are a little confusing, do as I described, you'll get there.


Modified by craigs06 at 8:33 AM 1/12/2009

[utfisherman]

Agree. Try TPS adjustment first. If still hesitates, check throttle linkage length adjustment and synchronization of throttle body butterflies. A factory service manual is very helpful with this proceedure. Craigs06 had a similar problem. See his thread from a month ago. http://www.bbcboards.net...iling

[craigs06]

I sent you the manual, see pages 38 and 39

[ghind]

fuel pumps. $100 or so for all from boats.net

Replace them don't rebuild

Search for how to test and fix (search by my username if you like)

[kld]

I just bought a contender with twin ox66 250 and the port engine sneezes. The sneeze get progressively worse as it warms up at idle.

I've cleaned the poppet, o2, new plugs, vst cleaned.

I haven't checked the fuel pressure yet but would love to have a copy of page 38 and 39 too.

Any chance this could be a head gasket???

Any tips appreciated.

[21XDC]

The lean sneeze is most likely a tps adj.