be sure you have tight connections on all fuel lines,you may not leak fuel,but might suck air,have you made sure the carbs are in sync,also make sure the timer base under the flywheel is advancing the timing and nothing linking the timerbase is broken
This is an interesting thread for me as I have run into the exact same situation on a 1963 Elgin/Sears/McCulloch 45 hp. I hope this is not stealing the thread as the same fix may apply to both and it doesn't seem like a brand-specific thing.
Took the boat out for the first time last week since buying it. I put-putted around the little marina bay we have for a while, then headed out in the river. Same deal, up to approximately 50% throttle, ran perfectly, above that, would pop and miss. Not dramatically, but it was noticeable and obviously not developing full power.
I continued about 3 miles up the river, which turned out to be a mistake, as the popping and missing started occurring at a lower throttle setting and then the engine died. Initially, I thought the spark plugs were probably fouled, as my two-stroke motorcycles from the 60s would always do that, but I was aware it might be fuel starvation also.
It did surprise me when the motor started up again right away. This ruled out fouled plugs. Because it immediately restarted I also was sure the motor wasn't overheated. I then got back to within a mile from the marina before it died again although it would only take a quarter throttle or so. I couldn't get it started on the water again after that.
I'm assuming that the lower fuel level in the tank (it had used about 1 1/2 gallon) had to do with the increasing fuel starvation. I did try squeezing the fuel bulb enroute, as I can reach it, but wasn't absolutely positive on the effect. For one 30 second period it did seem to reduce the popping.
Tomorrow I will remove the fuel pump and inspect it. There is a large bolt at the bottom which I assume leads to some type of screen or filter or at least a sediment sump. One thing I noticed is that the fuel line seems way too long and it has some overly complicated plumbing connections to the tank. I noticed at the store I could get a fuel bulb with the right adaptors built-in.
ONE QUESTION: If I can't fix this by servicing the fuel pump and hose, is it permissable to put a small electric fuel pump near the tank? The reason I ask that is I did exactly that with a Ford diesel truck that had a weak mechanical fuel pump. It 's been perfect ever since. The 45 hp Elgin wouldn't need a big Holley fuel pump like that; I would think just a little transfer pump would do. But I want to make sure there are no safety issues. You'd want to be sure the fuel pump didn't keep running once the engine died.
One other thing -- this was the very first time I'd taken any boat out other than a tiller boat as a kid, and the first time in river current. I'd purchased a Motor Guide 54# trolling motor just in case something like this happened, and it DID get used for that last half mile or so. As it was, I just barely made the little inlet to the marina before the current would have taken me past. Like barely made by ten feet or so. The motor gave me about the same speed as the current or just a tad more. It was kind of hard judging which way to point the boat to compensate. Like a crosswind landing in a plane.
Sorry for this long post. Car, I hope you get your 235 straightened out!
you have a classic fuel starve situation.check and be sure your fuel tank is vented ok,often the vents plug from bugs etc,if air cant get in,gas cant get out quick enough,a quick test there is loosen the cap,next,be sure your hoses arent kinkes anywhere,if you replaced the fuel lines,did you use 3/8 hose all the way,that engine needs lotsa gas,if you put an inline filter on,is it 3/8,the connections at the fuel tank often get plugged with debris,sometimes when brass fittings and the alum tank are put together,corrosion build up happens,did you try the squeezing the ball trick,you say you cleaned the carbs,did you take them apart and soak them in carb cleaning solution ,then blow through every passage with a carb spray,when you rebuilt the vro,did you change the pulse fitting that is on the hose to the engine,also the fitting at engine can get crud,as for the timerbase,look at the top of the throttle arm on the starbord side of the engine it should connectto the timer base with a little arm that has a plastic ball and socket,these plastics break,though I dont belive this is the prob,it can be in the fututre,keep ity in mind,check all the possibilities for fuel starving before tearing into carbs again,good luck,keep us posted
