L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

[TYLER HUNN]

Hi, I have a little problem, I hope. I am working on a 1991 bayliner capri with a 90 hp L-Drive. I had the boat running great about a month ago after replacing the head gasket. we couldnt get it to rev up to 5500 rpm's but we did get it to about 4100 @ 29 mph. We had a problem with the shift pivot screw and had the lower gear case rebuilt. I put everything back together and decided to do a decarb on the engine in an attempt to increase the rpm. I used a 2 gallon gas can and put one whole can of seafoam, 3/4 gallon of gas, and 3 ounces of 2 cycle smokeless semi synthetic. I ran the engine until it was warm then switched the gas line from the engine to my little mix. I ran this for about 15 minutes then i let it sit for 15 minutes. I restarted the engine and repeated this 3 times.

I put brand new spark plugs in. The engine seemed to run great on the trailer with the muffs hooked up. So we took it out for a test run today. It starts up great and idles decent but does try to die if its cold and it also seems like its kinda misfiring a little bit. It was driving good at 5 mph and the response was good but if i give it too much throttle too fast it dies. If I try to go higher than 1800 rpm it dies. It bogs down and dies unless I let off the throttle right away. I had it rev'd up to over 3000 without a load on it it and could of went higher.

I dont know but my thought on this is maybe its either starving for fuel or its getting too much fuel. last time we took it out it went through alot of fuel real fast so we were suspicious about that. I have the low idle adjustment screws on the front of the carburetor adjusted because the thing wont start and stay running unless it's just right. Well I think maybe the high speed adjustment or whatever needs to be adjusted but i dont know where it is. I remember seeing a small screw on the inside of the carbs but i cant get to it while they are connected on the engine. Im not even sure if that is what it is. so I dont know what the setting are supposed to be.

Everything I tried today didn't give me any improvement and we ran the boat for over an hour on the water at 5 mph so I know I ran all the old seafoam out that was in the bowls of the carbs. I really was expecting an improvement. Now its worse than before. Shifter works great forward reverse nuetral. But it just bogs out if I give it gas. It bogged out before too but not as bad when we ran it at 4000 rpm I had to slowly ease the throttle to get it that high and then 4000 was when the throttle was as far as it would go. I figure a decarb would increase the compression slightly. didnt check it though.

Ok so if anyone has any advice on where to check or what to do. Another thing in thinking is maybe its not grounded correctly and I recently installed an amp to a subwoofer and it is wammin pretty good but I dont know if that might be why or not. I dunno im kinda stumped and dont want to work on this stupid boat anymore it sucks.

 

[jerryjerry05]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

Do a compressio/spark test.Then check the fuel pump diaphram.Then the reeds.Post your results.J

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

I took the whole fuel pump apart and seems everything is fine. The diaphragm wasnt ripped or torn or anything. I was real gentle with it and put everything back together. I started it up and it will start up rev up and then die. If I try to give it gas manually from the carbs real quick before it shuts off it still just dies it is bogging out. I now have the carbs apart and on my table. Im not sure what to do here. lol I see a screw on the outside of the carbs i have all three all at 1 turn exact.

I see another screw to turn in the hole on the ouside on the side the air box connects.

Its # 19 in this Diagram CLICK HERE

So how do I adjust these carbs correctly. I know this has got to be what it is thats making this thing bog out.

 

[pnwboat]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

#19 is your idle mixture screw. Typical setting is 1 to 1 1/2 turns out from lightly seated.

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

ok so I put a flat head on the end of this one..

and i tried to on this one too but its stiff too

but it was real stiff so i dont want to turn it. i didnt budge either of them and am wondering if these are just to hold the pin in place. what are these for I am wondering why all of a sudden after i decarbed the engine it starts bogging. what could of happened.

Here are some more pics.....

this is the adjustment screw i see i have this at 1 turn exact on all of them.

the problem im having is it starts and idles if i adjust this right but when i hammer on the gas or even try to rev higher than 1800 rpm with a load on it it bogs out and wont rev any higher. but on the trailer with muffs it runs better and revs high. it kinda is misfiring a bit.

i just put new plugs in .

I have the floats and pins or needles or whatever out and they are clean .

I blew through the gas line and air comes out all three the same. its really clean i dont understand why its bogging out.

i bet im just being a dummy and its something simple please help. if its not the carbs i dont know what else could be wrong.

 

[pnwboat]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

I take that back. What's that saying....pictures speak 1000 words. The carburetor in the diagram is not exactly the same as yours. #19 in the diagram is the idle mixture screw. It is not the idle mixture screw on your carburetors. It's pretty easy to determine the idle mixture screws because they will have a spring underneath them to hold the setting. Looks like the screw that you were turning on the side of the carburetor is the idle mixture. Does it have a spring underneath it? I couldn't tell from the pictures.

The screw pictured inside the fuel bowl is your main jet. The other screw that I mistakenly identified as you mixture is actually an idle jet for the idle passages.

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

ok so after 4 hours of reading forums and all that good googling stuff ive come to think that my jets are clogged. The reason why is it was bogging out slightly before but it would very very slowly eventually plane out and get to 29 mph. I know its not supposed to bog out at all especially if its warm.

so i ran the decarb solution through it and now its worse so maybe it was already corroded or gunked up ( the high speed jets). and then now its built up more since maybe i knocked gunk free. im gonna try to take it apart again and take the jets and clean them. if i can even find what they are.

I have a 90ld91b model 90 hp l drive with tillotsen carbs

would those jets being clogged cause the engine to slightly misfire or jump about once every three seconds or so. ill hold it running and it feels smooth then its like a small firecracker going off on the inside real quick. the rpms go down like a hundred or so and then it runs smooth and does that sooo...

ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh ah

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

CLICK HERE this is the actual carberator i have. so im trying to clean the jets out what do i do?? lol sorry about that earlier. I thought that was the right one.

 

[pnwboat]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

The main jet is #20. Take a can of pressurized carburetor cleaner with the little plastic extension tube and squirt into all the passages, nozzles etc. If you can take some pressurized air and blow through after the carburetor cleaner.

By the way, have you performed a compression test? Seen many problems attributed to ignition and carb./fuel issues that ultimately were due to a cylinder that had very low or no compression because of a broken ring.

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

yeah i have another post i started a couple months ago. ive done everything dang near. lol

heres the link...... 1991 Bayliner Capri, 90 hp Force. No Power, bogs down and overheats.

Reason why i started a new thread is cuz the other one was getting to long. lol

compression good new head gasket i just had it running at 30 mph before i decarbed it with seafoam.

 

[pnwboat]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

I just re-read your other post. Now I get the whole picture. It kind of sounds like you're not getting enough gas.

Since you already have the carburetors off, go ahead and clean them out and put them back on. You'll probably have to adjust the linkage that connects all three throttle plates so that they are in perfect sync. Check them with the with the throttle cable from your control up front disconnected. Once you get it adjusted, hook it back up. If that fixes it, then you're good to go. I would also install one of those inexpensive inline filters between the fuel pump and carburetors.

If this doesn't fix it, the next thing I would look at is the one way check valves in your fuel pump. There are three of them. They have a tendency to stick. You can push on the plastic disk in the check valve with a tooth pick or something similar to check. If the plastic disc is the off white or have a slight orange tint, these are the ones that cause problems. They are still available and are relatively inexpensive.

NOTE: If you're looking for more WOT RPM's, you probably need a 17 pitch prop. It'll also help you got onto plane quicker.

 

[Babylon519]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

"You'll probably have to adjust the linkage that connects all three throttle plates so that they are in perfect sync."

Don't overlook what "pnwboat" said here. I have the L-drive 120 with 2 carbs and was having the same issue with bogging and poor performance. The major issue was exhaust- and head-gaskets, but getting those throttle plates perfectly in line made the difference between 36 mph and 42 mph on my 21-foot Maxum. On one of my carbs, the plate was going past WOT and had the effect of closing the throat again, meaning that the top two cylinders were working against the bottom two to some degree. I noticed yesterday I'm not getting top speeds again, so I'll check the throttle plates first. Hope this helps.

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

Oh WOW. thats what im thinking. I went and looked at all the diagrams for the boat because a ground wire was disconnected. I put it where it was supposed to go but that wasnt the problem. I noticed that there were jets on the carb aiming away from the engine and I noticed they sprayed into the airbox. I remembered a vaccuum line lookin hose connection on the bottom of the airbox but there was no hose for it. And i didnt here any leaks. I didnt even think it would be that. so I looked around and it was hiding behind the engine. I never even noticed it. I plugged it in and now it seems to work great. I disconnected all 3 spark plug wires and tested them with the engine running and got shocked hard by all three of them. lol. so I revd it up and now no more bogging. I havnt takin it in the water yet but i can tell. i can gun it and itll reach like 2500 rpm quick. before if i did this it would try to die. so i think its fixed I hope. I hope it goes faster than 29 with

 

[mick97]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

Hiya,

Mabe I have a similar problem.
Got a 85 capri,with a 85 force,85hp.

Runs ok when going slow..kick it down,and it boggs.
I hit the throttle up until it bogged down one day,and then went to the back of the boat,and tried to manually run the throttle plates.

Seemed like it was running great when i tried that.
I didn't have someone to steer,so couldn't do it too long.

So how do you adjust them?
Disconnect the linkage in the moror when the throttle is straight up and down,and then reconnect the throttle linkage?


Before i bought it it ran great.The last day when the guy brought it in,he hit a rock and really messed up the prop,so i put a new one on it.

Scotty from minnesota

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

Ok I took the bayliner out on the water yesterday to big ceder lake. First we went out and dropped it in the water and it was giving me **** and the battery died. we were embarresed. we drove back and charged it. we took it out started up hard first but after warmed up i dont even have to choke it. in nuetral I rev it up and it gets up quick. so I put it in forward gear give it gas and it bogs out. I am shocked. It runs way better with that vaccuum line hooked up but it still bogs down.

So I just decided to slam in to full throttle and it growled and tried to take off and the front of the boat lifts up and everything but then after like 2 seconds it tries to bog out. So now im thinking its a cylinder getting flooded and I checked the throttle plates and everything in sync. Everything is fine on the carbeurator side. I left the engine running and pulled each spark plug wire off and the bottom one shocked the crap outta me, the middle one shocked the hell out of me, but the top one wasnt really that bad. Im thinking that one of the coil packs is bad but i want to test it first and make sure sure.

Is there any way I can test this. I mean I dont want to tell my buddy to go buy three new coil packs and thats not it. we already have like 1000$ bucks in this boat. Any tricks to make sure its the coil pack?


Thanks

 

[WhiteRob]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

switch the coil packs around i.e move the top one and bottom one around, and try shocking yourself again, if it follows, it is a coil pack, if stays there cdi box

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

I am going to go pick up a electric tester and i am going to try to test the voltage or whatever from each coil pack to the spark plug. I found a shop that is right up the road from where we test the boat that has ignition coils so im gonna try to test it with a load on it and see if one of them is getting a smaller number. i hope ill let you guys know. i hope its not that cdi thing

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

ok im out on the boat and i tested the coil to spark plug with one of the ones that have a little bulb and it lights up . all of the coils have the same spark and look the same when I rev it up. I think we have to do it with a load on it. any ideas?

 

[pnwboat]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

Try this as a test. With it at idle, pull #1 spark plug wire. Does the idle speed change? If not, then there is something not right. Put #1 plug wire back on and pull #2. You should see a change engine speed/smoothness each time you pull a wire.

 

[TYLER HUNN]

Re: L-Drive (1991 90hp) Wont rev higher than 1800 rpm & bogs out and dies.

ok I just went to my friends shop and he gave us a electric voltage tester and an impact wrench and said test the stator wires and told me to take it out and replace it. whats your guys thoughts.


again it runs on all three and then when i slam it to full throttle it tries to bog out. but only when it has a load on it.

in nuetral it revs up like normal.