No Acceleration at WOT

[wolfpack6700]

I have a 92 88 HP Johnson that when I put it into gear it will not go above 3000 RPM or go very fast I have cleaned the carbs and fuel pump engine run great at Ideal it would also die out when putting into gear at times the bugger is it is a intermintent problem it was going good then all of sudden RPM died off any ideas? tks

 

[emdsapmgr]

When the engine bogs, or slows, check all 4 plugwires for spark. It's possible that it's dropping spark to one cylinder. Best to check the spark once the engine is fully warmed up and it's under load. Two good methods for checking spark when running: The cyl drop method (pull one spark plug wire off each plug one at a time) or use an inductive timing light to check for spark to each plugwire. Weak ignition components tend to fail once the engine warms up to normal operating temps. Usually, fuel problems are not intermittent. Also a good thing to check the engine's compression-a good set of numbers to baseline your engine during your ownership.

 

[suzukidave]

3000 rpm sounds like one cylinder bank is cutting out either from the overheat alarm or the neutral switch.

 

[emdsapmgr]

I don't believe any of the V4 crossflow engines that year had an rpm-limiting power pack which would inhibit rpm's over 2500 if the engine overheated. That was in the 90 degree V4 loopers and V6's only . The neutral switch in the control box prevents engine start when the shifter is in forward or reverse. Neither should have any impact on engine rpm's.

 

[wolfpack6700]

Changed out the plugs and wires no change checked the power pack there is a brown wire coming out for the temp switch and there are two temp switches on the engine also pushed in the primer while running got a very slight gain but no real change engine run great without load soon a I put it in gear though it just goes 2500-3000 RPM is it possible the high speed jet is somehow clogged and if so how do you clear it do you remove the lead seals on the carb?

 

[racerone]

I do not believe there are lead seals on these carburetors,----High speed jets are in the bottom of the float bowl and can be removed for cleaning without removing the carburetors .-----What are the results from a compression test and do you have spark that will jump a gap of 7/16" or more.-----That 7/16" gap is the only real acceptable test for spark !

 

[wolfpack6700]

Havent done a compression test boat still in the water nor spark test as for the same reason what about the fuel pump is it possible that its put back together wrong?

 

[emdsapmgr]

You can perform a simple fuel pump test. Next time out, run the engine till it begins to bog or slow. Have a buddy grab the fuel hose bulb and constantly prime it. If the engine runs fine at WOT as long as the fuel hose bulb is constantly primed, you have a fuel delivery problem-which certainly could be a weak fuel pump.