Throttle Issue

[jim520]

Went out yesterday and only has 2/3 throttle operational. The final 1/3 did nothing. Linkage appears to be
operating properly but can't get above 3800 rpm or around 20kts. Any ideas?

Thanks in advance for any suggestions.

Jim

 

[juggernaut1]

Old spark plugs / spark plug wires can result in a loss of rpm

 

[kvduff]

Could be an injector issue.


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[srl]

Do you have cruise control & is it on?

 

[jim520]

Plugs are OK and no cruise. Don't think it's an engine issue. It's as if the throttle works fine
for the first third of its travel after going into gear, but the final third of the travel it feels as if it isn't attached to anything and is not increasing engine speed. Where the cables attach to the linkage, all appears OK but is there something from there to the engine that may have disconnected?
all of your suggestions are really appreciated.

 

[scoflaw]

Verify that the cable is opening up your throttle body all the way, then move on from there

 

[jim520]

The cable is opening the throttle body all the way. Boat is going for engine/outdrive service and bottom paint
next week, so will ask the shop to have a look.
Thanks for the replies.

 

[CliffA]

I would suspect the distributor cap or rotor button or ignition sensor needs to be replaced.....I experienced a similar loss of rpm's due to an aging distributor cap and rotor....

cliff

 

[Molson]

Is the bottom clean?

 

[jim520]

Diver cleaned the bottom a couple of days before this problem surfaced. It sure seems like
its a throttle cable issue and not an engine issue. Guess we'll find out next week when we
get it to the shop. Thanks all.

 

[Korkie]

Jim520. I had the same problem. Changed out fuel filter / fuel pump due to frayed wire / the plugs. No change. Mechanic sprayed some starting fluid straight into the engine. If it smooths out / runs better - then have injectors cleaned. Had injectors cleaned and rpm went from 3500 at full throttle to 4450. My original issue was same as yours - no increase in rpms after 1/2 2/3 throttle. Injectors were $40 each to have them ultrasonically cleaned and tested. I was then advised this was from the fuel cooling modules being painted inside and the paint clogging up the injectors.n Having my port engine done in the off season.

 

[dpmulvey]

Good advise on the fuel module. I've had both replaced twice. POS!!!

At the insane price per...I'm surprised nobody with a CNC machine hasn't designed one from a block of bronze or stainless.

I believe Merc should have experimented with Marelon to see if the heat exchange rate would work.

 

[06320DA]

Jim520. I had the same problem. Changed out fuel filter / fuel pump due to frayed wire / the plugs. No change. Mechanic sprayed some starting fluid straight into the engine. If it smooths out / runs better - then have injectors cleaned. Had injectors cleaned and rpm went from 3500 at full throttle to 4450. My original issue was same as yours - no increase in rpms after 1/2 2/3 throttle. Injectors were $40 each to have them ultrasonically cleaned and tested. I was then advised this was from the fuel cooling modules being painted inside and the paint clogging up the injectors.n Having my port engine done in the off season.

Just curious - I am having the same issue in limited throttle but only sporadically. Did yours happen every time out?

 

[JVM225]

The cable is opening the throttle body all the way. Boat is going for engine/outdrive service and bottom paint
next week, so will ask the shop to have a look.
Thanks for the replies.

Dirty bottom?